Agent Enters into a Contract with Third Party on Behalf

Multiple Choice

Agent enters into a contract with Third Party on behalf of Principal.Agent told Third Party that this contract was being entered into on behalf of someone else,but did not identify Principal to Third Party.A couple of weeks later,Principal disappears and Third Party wants to hold Agent to the contract.Third Party can:

A) not recover from Agent because Agent had disclosed the existence of Principal
B) not recover from Agent because Third Party must first try to recover from Principal
C) recover from Agent because Agent had a duty to ensure that Principal performed on the contract
D) recover from Agent because Agent did not disclose the identity of Principal
E) recover from Agent because Agent acted on behalf of an undisclosed principal