Answer:
D
Explanation:
I say D because all of the other options are physical and environmental.
I think Greg needs to start small than go bigger on the excersise .
He shouldn't rush on the process and he should be careful.Take everything slow.
He should work hard but not to the point where he gets hurt again or more.
Remind him to stretch before he does
Excersising.
He should run shorter distances and than later increase the number of miles or laps he is running .
I hope I helped I am not really a athletic person though
While your friend's parent are ok to give alcoholic drinks to their kids and to you, maybe your parents aren't ok with having you a drink.