A nurse enters a client's room and finds him unresponsive. After notifying the rapid response team, which of the following actions should the nurse take first?

Choice A reason: Rescue breaths are not the first step in adult basic life support unless the client is confirmed to have no pulse and compressions have already begun. Choice B reason: Defibrillator pads are applied after confirming cardiac arrest and initiating CPR. They are not the first step. Choice C reason: Chest compressions are initiated only after confirming the absence of a pulse. Starting compressions without assessment may be inappropriate. Choice D reason: The first action after confirming unresponsiveness is to check for a carotid pulse to determine if the client is in cardiac arrest and requires CPR.