21. Which of the following statements concerning differences between continuous review (Q systems) and periodic review (P systems) inventory systems is FALSE? A. P systems require a perpetual inventory count, while Q systems require a periodic inventory counting system. B. In periodic review systems, orders are placed after an elapsed period, P, has passed, for a variable quantity of units. C. In continuous review systems, orders are placed for a fixed quantity of goods after a variable length of time has passed. D. Higher than normal demand during the order cycle leads to a shorter time between orders for Q systems, while in P systems it leads to larger order sizes. PART II: PROBLEMS: Please include the solutions in the ANSWER SHEET provided next page. Problem 1: Columbia Inc. purchases items from a vendor at a cost of $20 per unit. Average monthly demand is 400 units. It costs $50 to place an order and inventory carrying cost per unit is 10% per year. a. What is the optimal order quantity? b. How many orders will be placed per year? c. Determine the total cost of ordering and carrying inventory