What is the MAIN reason the author includes the section "The U. S. And The German U-Boat
Campaign"?

I would say the correct answer is B.

Explanation:

Sorry if I'm wrong"/

the protestant reformation's started in 1517, disturbing the religious and political order in europe´s catholic countries. the outcome was the european wars of religion prosecuted in europe in the 16th, 17th and part of the 18th century. nonetheless, uprisings, territorial disputes, and great power conflicts were also causes of the wars.  

abraham lincoln, according to anyone who was connected with agriculture, represented the worst of northern politicians. shortly after lincoln was elected, south carolina seceded from the union. they along with other southern states, retained their anger. in a way, it was their own fault: the democrats were split in the south. some wanted slavery to be extended in other states that were about to join the union and some didn't want it badly enough. lincoln had a solid backing from his party: the republicans were united in not wanting slavery to be expanded.