B and D
From SF documentation:
"No Access - Users can’t see price books or add them to opportunities. Use this access level in your organization-wide default if you want only selected users to access selected price books. Then, manually share the appropriate price books with the appropriate users."

A, B seems to be correct. High risk price book with no access setting will ensure no one can have unauthorized access. and sharing rule will ensure the access to the required.

Whats the correct ans?

B, and D - Agree

B, D

https://help.salesforce.com/articleView?id=sf.sharing_model_fields.htm&type=5