Why was the senate vote to declare the war of 1812 so close at 19 for and 13 against?

Below are the choices that can be found elsewhere:

A. Because many in the Senate, especially Federalists, believed the war was a bad idea.

B. Because some of the Senators had left Washington to return home for the summer recess, so they could not vote.

C. Because even though the British had agreed to attack Canada, they did not provide enough soldiers to do so.

D. Because the Secretary of War had irritated many of the senators by refusing to increase the size of the navy.

The answer is A.