In terms of formal powers in the realm of
foreign policy,
a. the president is entirely in charge
b. the president and congress share power
c. congress is entirely in charge
d. decisions are delegated to experts in the
bureaucracy

In terms of formal powers in the realm of foreign policy - b. the president and Congress share power.

Explanation:

Congress’s function is to act as an overseer over president's powers, which is guaranteed by the United States Constitution.

Although only Congress can declare war, there have been many cases where president have started a war without Congressional assent. For example, the Vietnam war lasted for a decade without official declaration of war. Also, Harry Truman (1884 – 1972) called Korean War a police action to get around congressional approval.