Melania tells Donald that she wants to buy Donald's house "on behalf of a party who wishes her identity not to be known." The party is Ivanka. With Ivanka's consent, Melania contracts with Donald on Ivanka's behalf to buy Donald's house. What is Melania's liability on this contract?

Group of answer choices

Melania is liable because Ivanka is an unidentified principal.

Melania is liable because Ivanka is an undisclosed principal.

Melania is not liable because she did not expressly agree with Donald that she would be.

Melania is not liable because Donald knew that Melania was contracting on behalf of another party.