Chanel Has the Option of Purchasing One of Three Products

Chanel has the option of purchasing one of three products: Brand A, Brand B, or Brand C.The price of each product is $10.If Chanel decides to purchase Brand A, the opportunity cost of this decision is

A) $20.
B) Brand B and Brand C.
C) zero if this is a frivolous purchase with no marginal benefit.
D) Brand B or Brand C, depending on which she considers to be the highest- valued alternative forgone.
E) Brand A.