Final answer:
The initial treatment for an unconscious, pulseless elderly man with cold skin and rigid muscles is CPR.
Step-by-step explanation:
The initial treatment for an elderly man who is unconscious, unresponsive, apneic, pulseless, with cold skin, rigid muscles, and a core body temperature of 89.6°F would be (A) CPR. It is important to start CPR as soon as possible in order to maintain blood flow to the vital organs, particularly the brain. CPR involves chest compressions and rescue breaths to provide oxygen and circulate the blood.