Charles offered to sell to Constance a personal watercraft that was not running very well for $500. Constance was interested but not willing to pay $500. She said "I'll give you $400." Charles said that he would think about it. Later, the same day, Charles asked Donna if she would be interested in purchasing the personal watercraft for $500. Donna said "Would you consider $450?" Charles said he would think on it. A few minutes later, Everett who had heard that Charles wanted to sell the watercraft accepted Charles' offer to sell for $500, and they agreed that he would pick up the watercraft the next day. A few minutes later, Constance called saying that she accepted Charles' offer to sell the watercraft for $500. A few minutes after that, Donna called and told that she accepted his offer to sell the watercraft for $500. Charles told Constance and Donna that he had already sold it, and they are angry, threatening to sue. Additionally, through no fault of anyone, there was a fire at Charles' home that night and the personal watercraft burned. Everett was not happy. A dispute ensues regarding what obligations Charles has, if any.

Which of the following is correct regarding the status of the negotiations between Charles and Constance prior to the fire? 

a.Charles made an offer which was rejected by Constance when she made a counteroffer for $400.

b.Charles had made an offer, and it was still outstanding because he did not revoke it before ending his initial conversation with Constance in which she offered $400.

c.Charles had made an offer but it was revoked because Constance did not immediately accept it.

d.Charles had made an offer which was still outstanding even though Constance had made a counteroffer for $400.