What Is Different Between the Heat Resulting from a Fire

Multiple Choice

What is different between the heat resulting from a fire and the heat produced by animals?

A) There is no difference.
B) Heat from animals results from internal work and heat from a fire comes from external work.
C) The heat that animals obtain from food is always less than heat obtained from burning food in a fire.
D) Energy from fires always produces heat, but energy use by animals does not always generate heat.