21. A small manufacturing firm that produces a line of office furniture requires casters at a fairly constant rate of 75 per week. The MRP system assumes a six-week planning hori- zon. Assume that it costs $266 to set up for production of the casters and the holding cost amounts to $1 per caster per week. a. Compute the EOQ and determine the number of periods of demand to which this cor- responds by forming the ratio (EOQ)/(demand per period). Let T'be this ratio rounded to the nearest integer. Determine the policy that produces casters once every T periods. b. Using backward dynamic programming with N = 6 and r = (75, 75, ... , 75), find the optimal solution. Does your answer agree with what you obtained in part (a)