Final answer:
The correct step when assessing an unconscious infant suspected to be in cardiac arrest is to look for no breathing or only gasping and simultaneously check for the brachial pulse for five to 10 seconds.
Step-by-step explanation:
Upon arriving at the scene where an infant is unresponsive, your first step is to indeed verify the safety of the scene and then assess the infant's condition. Since the infant is unresponsive and could be in cardiac arrest, you should proceed to look for no breathing or only gasping and simultaneously check for the brachial pulse. The correct action is d. for five to 10 seconds look for no breathing or only gasping while simultaneously checking for the brachial pulse. When checking for a pulse in an infant, the brachial artery is the recommended location instead of the carotid artery used in adults. This is located on the inner aspect of the upper arm and should be checked gently with two fingers. Once you ascertain whether there is no breathing or only gasping and have checked for a pulse, you will then take the appropriate next steps, which could include starting CPR and using an AED if available.