Final answer:
The nurse's priority in this situation is to stop ambulation and have someone bring a wheelchair for the client to ensure their safety.
Step-by-step explanation:
When a client begins to exhibit signs of confusion and weakness while being ambulated, the nurse's priority should be to stop ambulation and have someone bring a wheelchair (option a).
Stopping the activity and providing a wheelchair ensures the client's safety and prevents any potential further harm. Continuing to ambulate the client could lead to falls or injuries.
The nurse should then assess the client's condition for any underlying causes of confusion and weakness, such as low blood sugar or medication side effects. Once the client is stable, the nurse can resume ambulation at a slower pace if appropriate.