A 67-year-old man collapses in a shopping centre. Bystanders confirm he is unresponsive and not breathing normally. According to the 2020 Heart & Stroke CPR guidelines, what is the single most important immediate action for a trained lay responder?ACheck carotid pulse for 60 secondsBBegin high-quality chest compressions and call for an AEDCDeliver 2 rescue breaths before compressionsDPlace him in the recovery position and observeEWait for paramedics before doing anythingCheck my answer