The president may veto a bill, but if he does, he must
a. do so within five days.
b. give his reasons for doing so.
c. return the bill to conference committee.
d. none of the above.

The President may veto a bill, but if he does, he must give his reasons for doing so. The correct option among all the options that are given in the question is the second option or option "b". The President actually gets 10 days to veto any bill and if he does nothing within those 10 days, the bill gets passed automatically. 

Apolitical machine ~ apex