Bart owned 100 shares of a stock that was actively traded on a national stock exchange. Bart offered the 100 shares to any of a group of six people in a conversation at a party. The offered price was $72.50 per share, the price at which the shares had closed that day. No one really responded to the offer at that time. Ten days later when the shares were trading at $76.25, Marie, one of the offerees at the party, appeared at Bart's office saying that she accepted the offer. Bart claimed the offer no longer was available.

A. Did Bart make a valid offer? Why or why not?

B. Explain whether you think Marie has a valid claim for breach of contract against Bart.