Immutable storage for Azure Blob storage enables users to store business-critical data objects in a WORM (Write Once, Read Many) state.
Immutable storage supports:
Time-based retention policy support: Users can set policies to store data for a specified interval.
When a time-based retention policy is set, blobs can be created and read, but not modified or deleted. After the retention period has expired, blobs can be deleted but not overwritten.
Reference:
https://docs.microsoft.com/en-us/azure/storage/blobs/storage-blob-immutable-storage

Azure provides several disaster recovery tools for container-based workloads. To protect the multi-region Azure Kubernetes Service deployments from the regional outages, you need to implement Azure Traffic Manager. Azure Traffic Manager is a global load balancing service based on DNS.
It provides high availability and disaster recovery for container-based workloads. If one region fails, Azure Traffic Manager will direct the traffic to the secondary region. Traffic Manager routes any protocol (not only HTTP/HTTPS as Azure Front Door or Azure Application Gateway does) to the service endpoint's public IP address based on the routing method. Using geographic routing, it will direct the traffic to the closest AKS cluster and application instance. Then, the Load Balancer will take care of data delivery to the AKS.
Option A is incorrect because you need to use the Traffic Manager and Load Balancer services for multi-region AKS protection from the regional outages, but not the Azure Backup service.
However, the Azure Backup service protects the application data. Your container-hosted application uses Azure Storage disks or file shares, and Azure Backup will be an appropriate data recovery service.
Option B is incorrect because you need to use the Traffic Manager and Load Balancer services for multi-region AKS protection from the regional outages, but not the Azure VM Scale sets.
However, in case of node failures, Azure Kubernetes Service uses VM Scale sets to protect the nodes.
Option D is incorrect because you need to use the Traffic Manager service and Load Balancer services for multi-region AKS protection from the regional outages, but not the Azure App Service. Azure App Service is a fully managed web application hosting platform.
Reference:
https://docs.microsoft.com/en-us/azure/aks/operator-best-practices-multi-region#use-azure- traffic-manager-to-route-traffic
https://docs.microsoft.com/en-us/azure/traffic-manager/traffic-manager-configure-geographic- routing-method
https://docs.microsoft.com/en-us/azure/traffic-manager/traffic-manager-configure-geographic- routing-method

Explanation:
Box 1: Azure Lighthouse
To send data across tenants, you must first enable Azure Lighthouse.
Box 2: The Azure Monitor Agent

Explanation:
Box 1: Data path availability
Standard Load Balancer continuously exercises the data path from within a region to the load balancer front end, all the way to the SDN stack that supports your VM. As long as healthy instances remain, the measurement follows the same path as your application's load-balanced traffic. The data path that your customers use is also validated. The measurement is invisible to your application and does not interfere with other operations.
Note: Load balancer distributes inbound flows that arrive at the load balancer's front end to backend pool instances. These flows are according to configured load-balancing rules and health probes. The backend pool instances can be Azure Virtual Machines or instances in a virtual machine scale set.
Box 2: SYN count
SYN (synchronize) count: Standard Load Balancer does not terminate Transmission Control Protocol (TCP) connections or interact with TCP or UDP packet flows. Flows and their handshakes are always between the source and the VM instance. To better troubleshoot your TCP protocol scenarios, you can make use of SYN packets counters to understand how many TCP connection attempts are made. The metric reports the number of TCP SYN packets that were received.
Reference:
https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-standard-diagnostics

Azure Cosmos DB is Microsoft's fast NoSQL database with open APIs for any scale. It offers turnkey global distribution across any number of Azure regions by transparently scaling and replicating your data wherever your users are. The service offers comprehensive 99.99% SLAs which covers the guarantees for throughput, consistency, availability and latency for the Azure Cosmos DB Database Accounts scoped to a single Azure region configured with any of the five Consistency Levels or Database Accounts spanning multiple Azure regions, configured with any of the four relaxed Consistency Levels. Azure Cosmos DB allows configuring multiple Azure regions as writable endpoints for a Database Account. In this configuration, Azure Cosmos DB offers 99.999% SLA for both read and write availability.
Reference:
https://azure.microsoft.com/en-us/support/legal/sla/cosmos-db/v1_3/