B. Yes, because the acceptance criteria might need to be changed during the Solution Development Timebox.

Rationale:

In Agile Project Management, flexibility is key. It is important to prioritize work based on the value it provides and the necessity of the requirement. "Should Have" requirements are important but not critical, and they can be subject to change as the project progresses and as more information becomes available. Deferring the detailed setting of acceptance criteria for a "Should Have" requirement that might be dropped is a practical approach to managing workload and focusing efforts on the most critical aspects of the project first. This approach is in line with Agile's principle of responding to change over following a fixed plan.