"Trust Does Not Pay; in the Sense That on Average

"Trust does not pay; in the sense that on average returns to trustors is typically less than their initial endowments." This implies that:

A) on average trustees return less than one-third of the amount received in trust games where amounts sent by Senders is tripled by the experimenter.
B) on average trustees return more than one-third of the amount received in trust games where amounts sent by Senders is tripled by the experimenter.
C) on average trustees return exactly one-third of the amount received in trust games where amounts sent by Senders is tripled by the experimenter.
D) on average trustees reject the trustor's offer, resulting in both players getting zero in trust games where amounts sent by Senders is tripled by the experimenter.