All of the following are sources of energy for humans during exercise
a. stored atp
b. alcoholic fermentation c. lactic acid fermentation d. cellular respiration

The correct answer is (B) because humans cannot produce alcohol when they are exercising. If so, then everyone would be drunk all the time!

In all seriousness, though, (A) ATP is a source of energy created when a phosphate group breaks off; therefore (A) and (D) are incorrect. (C) is a source of energy because lactic acid is the result of lack of oxygen in muscle cells. Therefore (C) is incorrect.

I hope this helps!