If the man did not eat during the bike ride, why do you think that his blood glucose level never went below 4.5 mml/L

Due to less conversion of glucose into energy.

Explanation:

If the man did not eat during the bike ride, his blood glucose  level never went below because there is very little amount energy is used. If a person perform activities such as running and exercise etc, it requires more energy and for that more glucose is converted into energy and glucose level went down while on the bike ride very little amount of energy is needed and for that very little amount of glucose is converted into energy and the glucose level did not went below 4.5 mml/L.

i think it would be c

hope this : )