In Which of the Following Situations Can a Buyer Revoke

In which of the following situations can a buyer revoke acceptance of nonconforming goods?

A) The buyer accepted them without knowledge of the nonconformity because of the difficulty of discovering the nonconformity.
B) The buyer accepted them with the knowledge of the nonconformity,because they were the only option available in the market.
C) The price of the goods fell in the general market.
D) The buyer accepted the nonconforming goods because the seller couldn't cure the defect.