Given the above OCAPI definitions, which permission or permissions apply?

A Digital Developer selects "Show Orderable Products Only" in the Search > Search Preferences Business Manager module.
Which business goal does this accomplish?

A developer uses the call() instance method of dw.svc.Service to invoke a web service and implemented the callback methods defined by the dw.avc.ServiceCaliback class.
Which callback method is required only when invoking a SOAP service?

A Digital Developer is tasked with setting up a new Digital Server Connection using UX Studio in their sandbox.
Which three items are required to accomplish this task? (Choose three.)

A B2C Commerce developer has recently completed a tax service link cartridge integration into a new SHU site. During review, the Architect notices the basket calculation hook is being run multiple times during a single tax call.
What is the reason for the duplicate calculations being run?