4. A company is staffing its technical support department to handle service calls from its customers who bought one of its two key products, A and B. The customer population of the two products is 100,000 each. The tech service department operates 8 am to 6 pm daily (10-hour day). In a given day, a customer makes a service call with probability 0.1% (0.001) and each call lasts an average of one hour. The company wants to maintain a call blocking rate of 2%. Assume the traffic pattern meets the assumptions of Erlang-B. It costs the company $50 per hour for each Product A only specialist, $50 per hour for each Product B only specialist, $60 per hour for each Product A&B specialist. (a) If the company decides to hire Product A only specialists and Product B only specialists to handle the service calls of the two products, respectively, find its total hourly cost. (b) If the company decides to use Product A&B specialists exclusively to handle all the service calls, find its total hourly cost. (c) Compare the results of Part (a) and Part (b) and explain.