The title "commander-in-chief" refers to the president's role as the supreme leader of the armed forces. The correct interpretation of this role is:
c) the president has the power to give orders to all uniformed military officers.
While the president does have significant influence over military actions, such as directing military operations and ensuring national security, the formal power to declare war lies with Congress. The president also has a role in determining the military budget (b), but the phrase "commander-in-chief" specifically emphasizes command authority over the military. As for option (d), granting letters of reprisal is a historical power that is rarely used in modern times.