The president is the author of the nation's public policies in his or her role of

A commander in chief B chief legislator C chief of party D chief citizen

I think the correct answer from the choices listed above is option B. The president is the author of the nation's public policies in his or her role of chief legislator. He has the authority to influence members of Congress to make laws through veto power, signing a bill, speaking directly to Congress and meeting with individual members of the legislative body.