Answer:
The promise of democracy is that the people shall rule.
Trade was the motivating factor. The silk road accross Asia was besieged by bandits & required bribes to a number of nations to transport goods to & from Asia. Therefore a sea route would be a much safer & less expensive means of getting trade goods to & from Asia.
Choice A is wrong because only 26 presidents have served in the military.
Choice B is wrong because not all presidents have been governors.
Choice D is wrong since James Buchanan and Grover Cleveland were not married.
Therefore, Choice C is the correct answer.
... Can we get the descriptions?