The President of the U.S. has no constitutional responsibility to * a. make treaties.
b. act as Commander-in-Chief
c. appoint judges to the Supreme Court.
d. act as head of a political party.

The answer you are looking for is A: Make Treaties.

This is because Congress is actually responsible for making and maintaining treaties.
> The president must act as commander-in-chief
> The president does appoint judges to the Supreme Court — just think that our previous president elected a justice.
> And they run as the head of the political party, during the elections

C it's the response