You have an AWS OpsWorks Stack running Chef Version 11.10. Your company hosts its own proprietary cookbook on Amazon S3, and this is specified as a custom cookbook in the stack. You want to use an open-source cookbook located in an external Git repository. What tasks should you perform to enable the use of both custom cookbooks?

Answer options:

A.In the AWS OpsWorks stack settings, enable Berkshelf. Create a new cookbook with a Berksfile that specifies the other two cookbooks. Configure the stack to use this new cookbook.
B.In the OpsWorks stack settings add the open source project’s cookbook details in addition to your cookbook.
C.Contact the open source project’s maintainers and request that they pull your cookbook into theirs. Update the stack to use their cookbook.
D.In your cookbook create an S3 symlink object that points to the open source project’s cookbook.

Answer – A
To use an external cookbook on an instance, you need a way to install it and manage any dependencies. The preferred approach is to implement a cookbook that supports a dependency manager named Berkshelf. Berkshelf works on Amazon EC2 instances, including AWS OpsWorks Stacks instances, but it is also designed to work with Test Kitchen and Vagrant. 
For more information on Opswork and Berkshelf, please visit the link:
http://docs.aws.amazon.com/opsworks/latest/userguide/cookbooks-101-opsworks-berkshelf.html