At January 1, 2020, Marigold Inc. has beginning inventory of 4100 surfboards. Jake estimates it will sell 18000 units during the first quarter of 2020 with a 10% increase in sales each quarter. Marigolds policy is to maintain an ending inventory equal to 25% of the next quarters sales. Each surfboard costs $210 and is sold for $210. How many units should Marigold produce during the first quarter of 2020?

a) 18850

b) 18000

c) 15700

d) 13900

13900