Not sure how to arrive at answer D

Here is my thinking for why D is wrong. If the suggested retail price is $60 by the economists argument the person would only pay on average about 2/3 or $40 for the item. Here in D the person is simply saying that the would not sell it for less then $30. But $30 is still less than $40 so I initially thought that is supports the argument. But is it the possibility that more than half encompasses full retail value of $60? If that is not the case then I'm can't see how the answer choice is supported. I actually liked A because A opens up the possibility that the gift can be returned and thus has value similar to a gift card because if returned the amount paid a should bee received especially if there is a gift receipt.