can you please explain why the answer is c and not b.

I got b by taking 2% (0.02) x 1800 = 36

1800- 200-36=1564

A company purchased $1,800 of merchandise on July 5 with terms 2/10, n/30. On July 7, it returned $200 worth of merchandise. On July 8, it paid the full amount due. The amount of the cash paid on July 8 equals: $200. B. $1,564. C. $1,568. $1,600. E. $1,800