Which of the following access level would you provide for the test-developers group?

Answer options:

A.Reader
B.Collaborator
C.Contributor
D.Owner

Answer – A 
In the case studies we have the following information 
------------------------ Packages that are required by the application during the development phase will be installed by members of a group called test-developers
---------------------------. 
This means the member of "test-developers" group need to install the application hence we need to give "Reader" role only 

For more information on sharing and securing packages, please visit the below URL- 

https://docs.microsoft.com/en-us/azure/devops/artifacts/feeds/feed-permissions?view=azure-devops#feed-permissions-overview