You have an Azure DevOps project. Currently, you are using Azure Repos Git for source code version control. You are planning on using a third-party continuous integration tool to control the builds. Which of the following in Azure DevOps would you use for authentication?

Answer options:

A.Certificate authentication
B.Personal Access tokens
C.Shared Access Signature
D.NTLM Authentication

Answer – B 
If you need to integrate with external tools, you need to use Personal Access Tokens. Personal Access Tokens can be used to authorize external services into Azure DevOps. 
Options A, C and D are incorrect because the supported authentication method for external services is Personal Access Tokens. 
For more information on authenticating with Personal Access Tokens, one can browse to the following URL- 

https://docs.microsoft.com/en-us/azure/devops/organizations/accounts/use-personal-access-tokens-to-authenticate?view=azure-devops&tabs=preview-page