The correct answer is - B. rebuilding the German military.
In the 1930's Germany started to prepare what was going to be done in the coming years by reforming and rebuilding its military, in order to set a solid basis for further military actions. This was against the deal after the World War I, but the other great powers seemed to think that it is nothing serious if Germany militarizes, and that it will not have any consequences. They were obviously wrong, and they witnessed that in the years that followed, when Germany started a military expansion in order to satisfy its territorial ambitions.
The conclusion is that although a US president can technically send troops into a foreign country, in order to lawfully declare war, he or she must get the approval of Congress.
