Karen Decided to Sell Her Stair Step Exerciser, Because She

Karen decided to sell her stair step exerciser, because she wasn't using it as much as she thought she would. Her friend Lydia bought it from Karen for $100. The first day that Lydia used the exerciser, it fell apart, injuring Lydia's ankle. Lydia:

A) can sue Karen for breach of the warranty of merchantability, because the exerciser is not fit for the ordinary purpose intended.
B) cannot sue Karen for breach of the warranty of merchantability, because Karen did not expressly warrant the quality of the exerciser.
C) cannot sue Karen for the warranty of merchantability because this warranty was not implied in this situation.
D) cannot sue Karen, because they are not in privity of contract.