Which of these actions is necessary after contacting your supervisor about a cancellation?

Providing the client with make-up options is important as it demonstrates responsiveness to the client's needs and ensures continuity of care. This action supports the therapeutic relationship and shows that you value the client’s progress by offering alternative sessions to make up for the missed appointment. It also provides the client with options that can help minimize disruption in their treatment plan.

On the other hand, seeking a new client or setting up a meeting is not typically necessary just because of a cancellation. Additionally, ignoring the situation until the next session is not a professional practice; it fails to address the client's needs and disengages them from the therapeutic process. Therefore, offering make-up options is the most proactive and supportive action in this scenario.