The following information relates to Nibor Products for May 1984:

Opening stocks consisted of 25 units at a cost of £5 each . Goods purchased during the month amounted to:

40 units at £6 on 7 May, 55 units at £7 on 21 May , 100 units were sold during the month at £10 each .

The cost of goods sold for May using a Fifo stock valuation base is:

(a) £750;

(b) £1000 ;

(c) £650;

(d) £610 .