Why Does the President Have an Advantage Over the Legislative

Why does the president have an advantage over the legislative branch when they disagree?

A) The president is a unitary actor, while Congress is delayed and divided by collective action problems.
B) Presidents serve longer terms than members of the U.S. House and Senate and thus are more experienced in national politics.
C) Presidents can call on international leaders to criticize congressional actions.
D) The White House devotes more effort and staff resources to media relations than the U.S. Congress.