Slick Oil Producers Contracts to Deliver 1,000 Barrels of Lubrication

Slick Oil Producers contracts to deliver 1,000 barrels of lubrication oil to a buyer on or before June 15.On May 15,Slick informs the buyer that it will be unable to deliver the oil until after August.The buyer demands that Slick perform the contract,but to no avail.Which of the following best describes the buyer's rights in this situation?

A) The buyer must treat the contract as breached on May 15.
B) The buyer must wait until June 15 to determine if there has been a breach.
C) The buyer may treat the contract as breached on May 15.
D) The buyer may wait until June 15 to see if the seller performs.
E) The buyer has the option to either treat the contract as breached on May 15 or wait until June 15 to see if the seller performs.