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 that it was the final offer, it was valid for one month, and that he would not alter it. Two days later, Kent replied by saying that he was willing to pay $60,000 for the farm. A week after Luke received Kent's offer, Luke declined it. Ten days after that, 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 acted in an incompetent manner with regards to the offer.
c. Kent's acceptance was past the set time period in the offer.
d. Kent's counteroffer of $60,000 had rendered the offer for $65,000 invalid.