A company starts business on 1 January. In that month it buys 300 grecks at £40 each, then 200 at £50 each. On the last day of the month it sells 400 grecks. If it uses FIFO to value stock, what is the stock value at 31 January?

a. £4,500

b. £4,000

c. £5,000

d. £5,500