Why does the party with the presidency loose seats in off year elections

Midterm elections historically generate lower voter turnout than presidential elections. ... Midterm elections usually see the president's party lose seats in Congress, and also frequently see the president's intraparty opponents gain control of one or both houses of Congress.

the secretary of defense is the principal defense policy advisor to the president. under the direction of the president, the secretary exercises authority, direction, and control over the department of defense.

as you did not provide any choices for me to choose from to give you a direct answer, this is the only information i can provide.

your answer is b i think