Which of the following did NOT influence Truman's decision to drop the
atomic bomb?
A) An invasion of Japan would produce enormous U. S. causalities.
B) An invasion of Japan did not guarantee unconditional surrender.
C) Truman helped create the Manhattan Project.
D)Japan needed to pay a high price for attacking Pearl Harbor and
starting the war with the U. S.

I think the answer is C.

Explanation:

when world war i broke out across europe in 1914, president woodrow wilson proclaimed the united states would remain neutral, and many americans supported this policy of nonintervention. however, public opinion about neutrality started to change after the sinking of the british ocean liner lusitania by a german u-boat in 1915; almost 2,000 people perished, including 128 americans. along with news of the zimmerman telegram threatening an alliance between germany and mexico, wilson asked congress for a declaration of war against germany. the u.s. officially entered the conflict on april 6, 1917.