Your team currently has an Azure DevOps project and an Azure subscription. The subscription contains an Azure SQL database named testdb. They want to create a release pipeline. It would use the Azure SQL Database deployment task to update the database. Which of the following should they use as an artifact in the update process?

Answer options:

A.A BACPAC file
B.A DACPAC file
C.An LDF file
D.An MDF file

Answer – B 
You can use a DACPAC file for schema related changes. 
The Microsoft documentation mentions the following. 

Since this is clearly given in the Microsoft documentation, all other options are incorrect. 
For more information on Azure SQL database deployment, please visit the following URL- 

https://docs.microsoft.com/en-us/azure/devops/pipelines/targets/azure-sqldb?view=azure-devops&tabs=yaml