Two jigs are under consideration for a drilling operation to make a particular part. Jig A costs Rs. 800 and has operating cost of Rs. 0.10 per part. Jig B costs Rs. 1200 and has operating cost of Rs. 0.08 per part. The quantity of parts to be manufactured at which either jig prove equally costly is
(a) 800 (b) 15000 (c) 20000 (d) 23000