Please answer in full not with steps

Galaxy Co. sells virtual reality (VR) goggles targeted to customers who like to play video games. Galaxy procures each pair of goggles for $150 from its supplier and sells each pair of goggles for $300. Monthly demand for the VR goggles is a normal random variable with a mean of 160 units and a standard deviation of 40 units. At the beginning of each month, Galaxy orders enough goggles from its supplier to bring the inventory level up to 140 goggles. If the monthly demand is less than 140, Galaxy pays $20 per pair of goggles that remain in inventory at the end of the month. If the monthly demand exceeds 140, Galaxy sells only the 140 pairs of goggles in stock. Galaxy assigns a shortage cost of $40 for each unit of demand that is unsatisfied to represent a loss-of-goodwill among its customers.

a. Construct a simulation model to compute the monthly profit and unmet demand for Galaxy Co.

b. What is the average monthly profit resulting from its policy of stocking 140 pairs of goggles at the beginning of each month?

c. What is the proportion of months in which demand is completely satisfied?

d. Compare the average monthly profit resulting from stocking 105, 140, and 175 pairs of goggles at the beginning of each month. Which amount results in the largest average monthly profit?