According to john locke, which agreement did individuals enter into to form their own society

The fundamental principle still applies: labor is the ultimate source of all economic value. But the creation of a monetary system requires an agreement among distinct individuals on the artificial "value" frozen in what is, in itself, nothing more than a bit of "colored metal." This need for agreement, in turn, gives rise to the social order. 

a they donate money to humanitarian causes

c   they volunteer to alleviate suffering

d   they blame all muslims for not being able to keep their fellow muslims in line.

i am pretty sure it is a