The EMT shows she understands the regulation of temperature in the human body when she states:

A) "If the body becomes too hot or too cold, the brain will send instructions out to the body to either retain or lose heat."
B) "If the air outside the body is cold and the body is too hot, the cold air will move into the body to cool it."
C) "Since the cellular activity in the body constantly generates heat, the body must always be cooler than the air that surrounds it."
D) "For the body's cells to function properly, the human body must always be warmer than the air that surrounds it."

A) "If the body becomes too hot or too cold, the brain will send instructions out to the body to either retain or lose heat."