A part is made from solid brass rod of 38 mm diameter and length 25 mm. The machining time taken to finish the part is 90 minutes and labour rate is Rs.2 per hour. Factory overheads are 50 % of direct labour cost. The density of material is 8.6 gm per cubic cm and its cost is Rs1.625 per Newton. The
(a) Rs.8.40 (b) Rs.4.80
(c) Rs.14.80 (d) Rs.18.40