What indicates that the AED is ready to deliver a shock?

The correct indicator that the AED is ready to deliver a shock is when the device instructs you to stand clear. This verbal prompt confirms that the AED has analyzed the heart rhythm and determined that a shock is necessary to restore a normal rhythm in a patient experiencing a cardiac arrest. It is crucial for bystanders to be instructed to stand clear to ensure safety before delivering the shock.

While the other options may involve some level of activity from the AED, they do not specifically denote that it is about to administer a shock. The presence of noises or lights does not inherently indicate readiness for shock delivery. Warming pads could imply that the AED is functioning, but it is not a reliable sign that a shock is about to be delivered. Therefore, the distinctive command to stand clear is the key indicator that the AED is prepared for that critical next step in the resuscitation process.