One Manifestation of the Endowment Effect as a Reference Point

One manifestation of the endowment effect as a reference point is:

A) the willingness of an individual to trade a good based on his original endowment of that and other goods.
B) the willingness of an individual to buy a good based on the ownership of that good by other individuals.
C) the refusal of a person to sell a good for a price other than what she paid for it.
D) a difference between the price that a person is willing to pay for a good and the price that she es willing to sell the same good to someone else.