12. The unwritten agreement that people make to follow laws in exchange for themselves and their property is called A. habeas corpus.
B. the law of the land.
C. the social contract.
D. the Constitution.

C. Social contract

Explanation:

The social contract is the implicit agreement between the government and the citizens. In this agreement, both sides promise to do their part to make the area better. They also agree that if either side falls short then they can be punished, if through jail or revolts.

i believe the answer is:

-   william jennings bryan is a democrat while mckinley was a republican

at that time, the segment of population that choose for democratic party were the voters with low economic background and vice versa

- william jennings has support of populists and wants to have inflation to farmers while mckinley has support of bankers and businessmen , doesn't want inflation

the fixed value of gold make the large business able to stack up their gold without   being worried that it would devaluated.

- william jennings supported the silver standard while mckinley supported the gold standard

according to jenning, using other metal beside gold could the poor people to have more purchasing power and them advance in the society.