Bob is a farmer and is required to use the accrual method. At the beginning of the year, Bob has inventory, including livestock held for resale, amounting to $10,000. During the year, Bob purchased livestock totaling $3,000. Bob’s ending inventory was $4,000. Bob’s net sales for the year totaled $17,000. What is Bob’s gross profit for the current year?

a. $9,000

b. $17,000

c. $8,000

d. $13,000