Most Physically Active Adults in America Do Not Need to Eat

Most physically active adults in America do not need to eat more protein than inactive adults because

A) exercise does not increase protein needs as long as energy needs are met.
B) exercise increases the efficiency of recycling amino acids so that extra needs are met endogenously.
C) most people have high enough protein intake to provide the extra protein needed for active muscles.
D) most Americans are not sufficiently active to cause an increase in protein requirements.