Randolf, a wealthy connoisseur of arts, was invited to an art exhibition. He became very interested in one of the showcased paintings and approached the manager to buy the piece. While he was interested in the painting (catalogue number 1201), the art gallery's manager mistakenly assumed he was interested in another piece. When it was the time to complete the transaction, the manager realized that he had instead sold and delivered the wrong painting. He immediately clarified this with Randolf. In this instance, the contract can be canceled by either party for?

a. mutual mistake
b. unilateral mistake and mutual mistake
c. mutual or unilateral mistake
d. mutual mistake and misrepresentation