Why Does Your Body Often Have Excess Heat to Get

Why does your body often have excess heat to get rid of?

A) The basal metabolic rate at rest produces excess heat.
B) Any activity that raises the metabolic rate above basal produces excess heat.
C) Because our bodies are well insulated, they can easily overheat.
D) We live in relatively warm climates.
E) Because we are mammals, and mammals are "warm blooded."