D. historical because a historical novel would be based on a actual event or a specific period.
Answer:
Germany wanted to open a front in the Americas. With the "distraction" of Mexico attacking, it may lead to US cutting off supplies and troops that would have gone to the Western Front to fight to defend their own homeland. As the Allies were heavily dependent on US products & material, this shortage of supply would lead to a weakened front, easing the front for the Germans to take advantage of.
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President Andrew Johnson had long wanted to dismiss the Secretary of War, Edwin M. Stanton. Stanton was the only member of Johnson's cabinet who supported the Radical Republicans' program for reconstruction. On August 12, Johnson suspended Stanton. In his place, Johnson appointed the popular General Ulysses S. Grant Secretary of War.
Congress overruled Stanton's suspension and Grant resigned his position.
Ignoring Congress, Johnson formally dismissed Stanton on February 21, 1868
