Day	1	2	3	4	5	6	7
Number of units	150	180	120	250	160	120	150

For a truck that can carry 2000 cubic feet, hiring cost per day is Rs 1000. Storing cost per cubic feet is Rs 5 per day. If the storage cost is reduced to Rs 0.8 per cubic feet per day, then on which day/days, the truck should be hired?
(A) 4^th                  (B) 7^th                 (C) 4^th and 7^th                    (D) None these