Problem Statement:

Creator should be able to create a public question while working on questionset
The public question should be available for re-use.
While adding questions from question bank, creator should be able to modify the question slightly/fully.

Solution:

Public Question Creation:

While creating question under questionset, Creator will have an option to mark the question as public.
update hierarchy api will be enhanced to accept public visibility for question.
When QuestionSet will be sent for Review, all questions with parent visibility and draft version of public questions should be submitted to Review.
When QuestionSet will be sent for Publish, all questions with parent visibility and public question created should be published.
parent metadata will continue to exist for public question as well.

Using Question from Global Question Bank:

Creator will have a search option to search relevant question from global question bank.
Creator can use the question from global question bank as is.
If Creator wish to modify (partially/fully) the public question, the question object will be cloned (deep copy) and all modification will be applicable on the copied object.
Copied object will have the same visibility as the original one. It means it will be public by default.
Copied object will have the parent visibility by default unless creator mark it as public.

Code Changes:

Single Sourcing Solution