Luke Offered to Sell His Farm to Kent at $75,000

Luke offered to sell his farm to Kent at $75,000, an offer which Kent declined. A week later, Luke offered to sell the farm for $65,000, stating it was the final offer that would be valid for one month only. Two days later, Kent offered to pay $60,000 for the farm. Luke received Kent's offer a week later and he declined it. After ten days, Kent agreed to buy the farm for $65,000, but Luke refused to sell the farm. Kent decided to sue Luke for a breach of contract. The judge ruled in favor of Luke. Which one of the following is the reason for the ruling in Luke's favor?

A) Luke's original offer of $75,000 is still valid, even though rejected.
B) Kent's counteroffer of $60,000 had rendered the offer for $65,000 invalid.
C) Kent's acceptance was past the set time period in the offer.
D) Kent acted in an incompetent manner toward the offer.