A. no CPR.
Hands-only CPR can be more effective than doing nothing in a cardiac arrest situation, as it provides circulation to the brain and other vital organs. While conventional CPR (which includes rescue breaths) has its own benefits, especially in certain cases, hands-only CPR is preferable in many scenarios, particularly for untrained bystanders. An AED is also crucial but is not a replacement for CPR; rather, it is used in conjunction with it.