The correct answer of these choices is, "Your body wouldn't fight off the infection as quickly/efficiently as it could."
Explanation:
This is because, when you get sick the reason you get a fever is because your body is working overtime to kill off your illness, and the more work your body does the more heat it gives off. So, if you were sick and you didn't have a fever, then it means your body isn't in that overtime mode to kill off the illness, and thus not working as quickly and efficently as it could.
