The correct answer is D) Keep the person lying down and at a comfortable temperature. When a person goes into shock, the body's blood vessels dilate, causing blood to pool in the extremities and reducing blood flow to vital organs. Keeping the person lying down helps maintain blood flow to the brain and heart. Additionally, maintaining a comfortable temperature helps prevent further heat loss, which can worsen the effects of shock. The other options are not appropriate - elevating the head and feet can actually reduce blood flow, stimulants can be dangerous, and keeping the person awake may be difficult and is not the primary concern.