Final answer:
The appropriate action would be to place a surgical mask on the client and transport them to the CT department at the specified time.
Step-by-step explanation:
The appropriate action for the nurse caring for a client with active tuberculosis and under airborne precautions, who requires a computed tomography (CT) examination, would be to place a surgical mask on the client and transport them to the CT department at the specified time (option D).
Placing a surgical mask on the client helps to prevent the spread of tuberculosis to others during transport. The client should follow respiratory hygiene and cough etiquette, covering their mouth and nose with a tissue or their elbow when coughing or sneezing, to further prevent the spread of infection.
It is not necessary to request the examination to be done at the bedside (option A) or question the need for the examination (option B). The nurse does not need to notify the CT department in advance to remove other clients and staff (option C) because the client is already under airborne precautions.