Please select steps to integrate the Dataverse events with Azure Function that would avoid the 503 Status code errors.

Answer options:

A.Register New Step with Synchronous PostOperation stage of execution
B.Register New Assembly
C.Register New Step with Asynchronous PostOperation stage of execution
D.Registry New Service Endpoint
E.Register New Step with Asynchronous PreOperation stage of execution
F.Register New Web Hook

Correct Answers: C and F 
The Dataverse provides a way to publish events to external services by using web hooks. You can Register the New Web Hook using the Dataverse`s Plug-in Registration Tool and attach it to the Dataverse events. After a web hook registration, you need to Register a New Step when the web hook transfers the data to the Azure Function. 
There are three stages in plug-in event pipeline execution: PreValidation — an initial stage before the main operation. You can include the logic for canceling the event before the data transaction.
PreOperation — the next stage before the main operation but within the data transaction. You can make changes to the data in operation.
PostOperation — the stage after the main operation and still within the data transaction. You can call other actions using the Organization service before the message returns to the caller.
The data transfer using a web hook has a 60 seconds timeout. If a web hook cannot rack the endpoint within this time, the 5xx Status code returns back. To avoid this type of error, you need to register the New Step for the WebHook with the Asynchronous PostOperation stage of execution. 
All other options are incorrect. 
For more information about the Dataverse webhooks integration, please visit the below URLs: 

https://docs.microsoft.com/en-us/powerapps/developer/data-platform/register-web-hook
https://docs.microsoft.com/en-us/powerapps/developer/data-platform/use-webhooks
https://docs.microsoft.com/en-us/azure/azure-functions/functions-scenario-database-table-cleanup