Karen Offers to Sell Gary 100 Stocks That Are Fluctuating

Karen offers to sell Gary 100 stocks that are fluctuating rapidly hour by hour. Gary receives the offer an hour before the market closes. Which of the following would be a valid contract?

A) Gary accepts by fax two hours after the market has opened the next morning and after learning that the stock has jumped up significantly. He agrees to buy the stocks at the current price.
B) Gary accepts to buy the stocks at the pre-fixed price.
C) Gary accepts to buy the stocks an hour before midnight.
D) Gary accepts on the spot. Karen's office catches fire and the stock papers all burn up.
E) Gary accepts immediately. That very night, the stock market makes it illegal to buy quantities less than 350 shares.