Fred Twain sends the following e-mail to Ralph Barnes: "Will sell you my 2006 Audi A4 for $23,500, will carry or take cash. This offer to remain open until November 11, 2007." Ralph responds, "I know how much you love that car. I'll think about it." On November 12, 2007, Ralph e-mails Fred and writes, "Fred, I am ready to buy your car." Fred responds, "Ralph, I sold the car this morning because I didn't hear from you."
a. Fred has breached a contract because Ralph accepted.
b. Fred was required to notify Ralph before he sold the car to someone else.
c. Ralph no longer had the power of acceptance.
d. both a and b