Your company has an Azure DevOps project named tests. The project contains pipelines defined in Azure Pipelines that picks up code from GitHub repositories. You have to ensure that developers are able to receive Microsoft Teams notifications when there are failures in the pipeline. 
You have to complete the below command for this purpose 

Which of the following needs to go into Slot 2?

Answer options:

A.https://dev.azure.com/testsorg/tests/
B.https://dev.azure.com/testsorg/tests/_build?definitionId=123
C.https://dev.azure.com/testsorg/tests/_packaging?definitionId=123
D.https://dev.azure.com/testsorg/tests/_work_items?definitionId=123

Answer – B 
Here you need to give the build URL. The build URL will also have the definition ID for the build to subscribe to. 
Options A,C and D are all incorrect because they don’t subscribe to the build URL. 
For more information on integration of Azure DevOps pipelines with Slack, you can refer to the below link 

https://docs.microsoft.com/en-us/azure/devops/pipelines/integrations/microsoft-teams?view=azure-devops