Price Books don't have sharing rules

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

B is the only way to limit the use of price books (assuming users have Edit on Opportunity) https://help.salesforce.com/s/articleView?id=sf.sharing_model_fields.htm&type=5
D will be easier to maintain than manual sharing (criteria-High Risk, share with-the trained staff's group/role)
But anyway, those options work together (not two ways)

Shut up test.

https://www.freecram.net/question/Salesforce.Sharing-and-Visibility-Designer.v2020-08-19.q78/universal-containers-uc-implemented-sales-cloud-and-requested-that-only-certain-branch-staff-trained

A. Set Price Book Organization Wide Default to View Only and share the price book (High Risk) with the trained staff.
By setting the Price Book Organization Wide Default (OWD) to "View Only," you ensure that all users can see the price books but cannot necessarily use them when creating opportunities. You can then share the specific high-risk product price book with trained staff, granting them the ability to use this price book when creating opportunities. This method ensures that only staff with the necessary training can sell high-risk products by controlling access to the relevant price book.

D. Share (High Risk) price book with the trained staff via sharing rule.
Implementing a sharing rule for the high-risk price book allows for automated sharing based on defined criteria, such as role, group, or specific criteria that identify trained staff. This method facilitates easier management of access as staff qualifications change or as new staff are trained, ensuring that only those with the proper training can access and use the high-risk price book when creating opportunities....

It's B&C.

Price Book Access Levels
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.