The maximum level of inventory of an item is 100 and it is achieve with infinite replenishment rate. The inventory becomes zero over one and half month due to consumption at a uniform rate. This cycle continues throughout the year. Ordering cost is Rs.100 per order and inventory carrying cost is Rs. 10 per item per month. Annual cost (in Rs.) of the plan, neglecting material cost, is
(a) 800 (b) 2800
(c) 4800 (d) 6800