<span>b. They were used to pay the Spanish.</span>
The answer for this would be the individuals on the island would all appear very alike to individually or each other, and they may demonstrate uncharacteristically high incidences or manifestation of traits that are unusual in the universal human population.
People agree to social contracts because they establish governments which in turn establish a sense of order and security. It establishes a set of rules which makes people more comfortable when they have some to follow.
Now I'm not 100% sure here but C is your best bet