NUSCOOP is the NUS-owned bookstore that sells Decision Analysis (DA) textbooks to NUS students The retail price of the DA textbook is $130 per copy and the demand for the DA textbooks is uncertain. However, the past sales data can provide a probability distribution estimate of the demand for the DA textbooks to determine the order quantity of the DA textbooks 1. At the beginning of each semester, NUSCOOP can order 60, 80, or 100 copies of the book from the publisher. Moreover, the publisher offers quantity discount. For NUSCOOP, the ordering costs under different ordering quantities are listed in the following table #of the books 60 80 100 ordered Ordering costs $6100 $7700 9100 NUSCOOP can either sell the book at the retail price ($130 per copy) or offer 10% discount ($117 per copy). The demand distributions under different selling prices are listed in the following tables. The demand distribution for the textbook when the selling price is $130 per copy 2. Demand Probability 0.6 0.4 70 90 The demand distribution for the textbook when the selling price is $117 per copy Probability 0.15 Demand 80 100 0.85 Any unmet demand for the textbook will be lost. 3. There are two decision variables in this decision problem: the ordering quantity and the selling price of the textbook a) Create a decision tree for this decision problem. (5%) b) Solve your decision tree model and find the optimal ordering quantity and selling price of the textbook for NUSCOOP. (5%) IfNUSCOOP can return unsold textbooks to the publisher for a refund of $80 per copy, c) find the optimal ordering quantity and selling price of the