A company normally sells its product for $20 per unit. However, the selling price has fallen to $15 per unit. This company's current inventory consists of 200 units purchased at $16 per unit. Replacement cost has now fallen to $13 per unit. What is the amount of the lower cost of market adjustment the company must make as a result of this decline in value?

a.$1,000.

b.$1,400.

c.$400.

d.$600.

e.$800.