An Agent with No Express, Implied, or Apparent Authority to Do

An agent with no express, implied, or apparent authority to do so identified himself as an agent for his principal, and on behalf of his principal bought a computer. The principal refused to ratify the contract. On these facts, which of the following is true?

A) The agent could be sued by the seller of the computer for breach of his warranty of authority.
B) The seller of the computer could sue the agent for breach of contract for saying he was an agent.
C) The seller could sue the principal for breach of warranty of authority.
D) The principal would have to pay for the computer because the agent was an agent for that principal.
E) By exceeding his authority, the agent has become the buyer of the computer himself.