The correct responses to why it is challenging for actors to depend solely on their own judgment during a performance are:
- They cannot observe their performance in real-time.
- The director has a wider view, so they can see how the individual performances fit together.
- They may not have had sufficient rehearsal time.
These points highlight the limitations an actor faces in assessing their own performance in the context of the entire production. Lack of real-time feedback, the director's perspective, and insufficient rehearsal time all contribute to the challenges actors face in relying solely on their own judgment. The option about lacking confidence, while a potential issue for some actors, is not universally applicable or directly related to the challenges of judgment during a performance.