Explanation:
Box 1: Yes
A topic has trigger phrases and conversation nodes. Trigger phrases are phrases, keywords, and questions that a user is likely to type that are related to a specific issue. Conversation nodes define how a bot should respond to a trigger phrase and what it should do.
Box 2: No
A flow can only be called from a topic located in the same Microsoft Dataverse environment as your bot.
Box 3: Yes
Once you're satisfied with your bot's content and quality, you can publish your bot to allow users to engage with your bot. You must publish your bot at least once for the user to chat with the bot in Microsoft Teams.
Each time you want to update your bot's content, you publish it again from within the Power Virtual Agents app in Microsoft Teams. This will update the bot's content with the latest changes you have made.
Reference:
https://docs.microsoft.com/en-us/power-virtual-agents/authoring-create-edit-topics
https://docs.microsoft.com/en-us/power-virtual-agents/advanced-flow
https://docs.microsoft.com/en-us/power-virtual-agents/teams/publication-fundamentals-publish-channels-teams

After you successfully train your model, you have to publish it to make it available. All users in your current environment will be able to use your published model when you publish it.
https://learn.microsoft.com/en-us/ai-builder/publish-model

A) Customer self-service portal: A customer self-service portal enables customers to access self- service knowledge, support resources, view the progress of their cases, and provide feedback.
B) Community portal: A community portal leverages peer-to-peer interactions between customers and experts to organically grow the catalog of available knowledge from knowledge base articles, forums, and blogs as well as providing feedback through comments and ratings.
C) Partner portal: A partner portal allows every organization with resellers, distributors, suppliers, or partners to have real-time access to every stage of shared activities.
Ref: https://learn.microsoft.com/en-us/power-apps/maker/portals/portal-templates

Explanation:
Box 1: Yes
Only if you would like to share your connector with all users of Logic Apps, Microsoft Flow, and PowerApps, you can submit your connector for Microsoft certification. Microsoft will review your connector.
Box 2: Yes
Connectors created in Microsoft Flow are available in PowerApps. Likewise, connectors created in PowerApps are available in Microsoft Flow.
Box 3: No
If you would like to share your connector with all users of Logic Apps, Microsoft Flow, and PowerApps, you can submit your connector for Microsoft certification. Microsoft will review your connector.
Reference:
https://docs.microsoft.com/en-us/connectors/custom-connectors/