With Respect to Ratification, Which One of the Following Statements

With respect to ratification, which one of the following statements is true?

A) Irving has been given authority to contract for the purchase of 1,000 jade tiles at up to $18 a piece. Instead, he buys from Cassiar Jade Co. 1,200 jade tiles at $18.25 a piece. When Cassiar Jade finds out that Irving has exceeded his authority, it sells the tiles to Interior Designs Co. After Cassiar has sold the tiles, Irving's principal can no longer ratify the contract.
B) The ratification by the principal must be in writing to be effective.
C) Ratification is the act of a principal approving a contract when his agent has exceeded his authority or acted without authority, and such approval gives the agent authority retroactively to the time the agent made the contract.
D) The only limitation on a principal's right to ratify is the power of the third party to set a time limit within which that ratification must take place.
E) When an agent, without the authority of his principal, has entered a contract for three computers and two printers, and the principal wants the computers but not the printers, he can ratify part of the contract.