Why Was the Defendant in Smith V Hughes Not Liable

Why was the defendant in Smith v Hughes not liable to pay the contract price for the new oats?

A) Old oats were discussed before the oral contract was concluded.
B) Old oats were not discussed but the seller knew that the buyer believed that the oats were in fact old.
C) The seller knew that the buyer was contracting for old oats.
D) All of the options provided are correct.