Answer:
B. Executive
Step-by-step explanation:
In the past, Congress (which belong to the legislative branch) was the one that commanded the US military. But, ever since the War Powers Resolution was created in 1973, the highest command of the military fall to the control of the President (which belong to the executive branch).
The president of United States held the status as the 'Commander in chief' within the military, The president will have the final say regarding with whom Us military should go to war, when they should retreat, or when they can use the weapons of mass destruction.