Corine Engaged Datz as Her Agent

Corine engaged Datz as her agent.It was mutually agreed that Datz would not disclose that he was acting as Corine's agent.Instead he was to deal with prospective customers as if he were a principal acting on his own behalf.In this way he made several contracts for Corine.If a third party were to file a lawsuit on one of the contracts,which of the following statements would be true?

A) Corine is disallowed from ratifying Datz's contracts in order to transfer liability.
B) Datz has no liability once he discloses that Corine is the real principal.
C) The third party can hold only Datz liable since the third party believed that Datz was the principal.
D) The third party may choose to hold either Datz or Corine liable.