answer all please.

13. Which of the following is not an assumption made in the M/M/1 queuing model? A. Customers arrive according to a Poisson process B. Service time follows an exponential distribution C. The waiting area can accommodate any number of customers D. FCFS (First-Come, First-Served) is used for determining which customer to serve next E. None of the above is the answer 14. The service profit chain suggests that the internal service quality (i.e., the environment in which employees work) drives the satisfaction, retention, and productivity of employees and ultimately the profitability and growth of the service firm. A. True B. False 15. The higher the variability in service time, the longer the average customer waiting time. A. True B. False 16. If the service capacity is greater than the customer arrival rate, there will be no customer waiting in line. A. True B. False 17. A swim lane flowchart can be used to show how the process flows across different people or departments. A. True B. False 18. To use the M/M/1 or M/G/1 queuing model in analyzing a waiting line system, we need to make sure that the distribution of customer inter-arrival times is close to an exponential distribution. A. True B. False