On July 18, Snowco, a shovel manufacturer, received an order for the purchase of 500 snow shovels from Acme, Inc., a wholesaler. Acme had mailed the purchase order on July 15. The order required shipment of the shovels no earlier than September 15 and no later than October 15. Typed conspicuously across the front of the order form was the following: "Acme, Inc., reserves the right to cancel this order at any time before September 1." Snowco's mailed response, saying "We accept your order," was received by Acme on July 21. As of July 22, which of the following is an accurate statement as to whether a contract was formed? 
No contract was formed, because of Acme's reservation of the right to cancel.  No contract was formed, because Acme's order was only a revocable offer.  A contract was formed, but prior to September 1 it was terminable at the will of either party.  A contract was formed, but prior to September 1 it was an option contract terminable only at the will of Acme. 