Final answer:
The AP's action that requires the nurse to intervene is excessive movement of the client's limbs.
Step-by-step explanation:
To turn a client onto the right side, the assistive personnel (AP) and nurse should follow certain guidelines to ensure patient safety. In this scenario, the AP should avoid moving the client's limbs excessively, which can cause discomfort or injury. Therefore, action C by the AP requires the nurse to intervene.