Fred assembles computers in his garage and sells them. He makes an agreement with Alpha Company under which Alpha will deliver 100 keyboards. The agreement does not specify when payment is due. Which of the following is true?
a. Fred has no obligation to pay, because there was no "meeting of the minds" and no contract was formed.
b. Fred must pay within ten days of making the agreement.
c. Fred must pay within ten days of accepting the keyboards.
d. Fred must pay within a commercially reasonable time.