Which executive department leader would the president most rely on for analysis of another nation's political situation and for advice on how to handle diplomatic situations with that country?

A)Secretary of State

Explanation:

necessary and proper clause. the congress shall have power to all laws which shall be necessary and proper for carrying into execution the foregoing powers, and all other powers vested by this constitution in the government of the united states, or in any department or officer thereof.

bless you your highness