Jack Has Been in the Business of Selling Carpeting for 20

Jack has been in the business of selling carpeting for 20 years.He calls Bob, who is opening another branch of his furniture stores, and offers to sell him 100 yards of carpet at $20 per yard.Bob agrees and sends back the following letter confirming the deal: Dear Jack:
As we discussed on the phone January 3, we accept your offer of 100 yards of Saxony "heather blue" carpeting at the rate of $20 per yard.We also reserve the right to purchase any additional yardage we need to carpet our other showroom facilities at the same rate for one year from that date.Very truly yours,
Bob
Which of the following is true?

A) There is a contract for only 100 yards of carpeting.
B) There is a contract for 100 yards PLUS the additional yardage.
C) There is no contract since Bob made a counteroffer.
D) There is no contract because the additional term is too uncertain to become a contract term.