What activities are required to implement a hook method?

You develop an SAPUIS app that can be extended. To allow your customer to customize notifications, you set up a hook method.

What activities are required to implement a hook method? Note: There are 3 correct answers to this question.
A . Add a code snippet to check if the method exists and execute it
B . Create a ifile in the Util folder to allow the customer to add custom code.
C . Modify the bootstrap option to allow multi-layer extensions of the custom code.
D . Identify a strategic location in the controller for the customized code
E . Define a new function name ensuring itis reserved for the extension.

Answer: A, D, E