Mein Co.'s sales totaled $300,000 for the current year. Mein's cost of goods sold was $150,000. Mein's accounts receivable balance was $20,000 on January 1 and $30,000 on December 31. What was Mein's accounts receivable turnover rate for the current year?

a. 10 times.

b. 6 times.

c. 15 times.

d. 12 times.