help!CE Econ

as question said that
that coupon is transferbale

the correct answer is D
because
the opportunity cost of using the coupon is the money that can be earned by transfer it to somebody
if the price of the buffet decrease
the price of coupon must decrease
the price of coupon is the opportuninty cost of using it
so D is correct

A is not correct
because if he loses the coupon
he will lose the money that can be earned by transfer it

B is not correct
that coupon is not a free good
as there is a cost to provide that buffer dinner
such as food cost

C is not correct
his opportunity cost of using the coupon is the money that can be earned by transfer it
so it is not zero

In my point of view, I think none of the answer is correct......

Answer A is wrong: If he loses the coupon, he will lose a chance to have a free buffet.

Answer B is wrong: The coupon is not a free good. This is because the quantity of the coupon is insufficient to satisfy all the people's wants. All people want to have a coupon too. They perfer to have one.

Answer C is wrong: The opportunity cost of using the coupon is not zero. This is because he may sell the coupon to earn more money. He may also use the time for enjoying the buffet to do other things, in order to earn more money.

Answer D is wrong: The price of the chosen option decrease will NOT affect the opportunity cost of the chosen option. The O. C. will ONLY BE AFFECTED if the price of highest valued option foregone change.

This is all reference. I am just a student which is F.4 next year...