Answer:
B.
Explanation:
Queuing problems refers to when the service that is being provided doesn't match the level of demand. Based on the information provided within the question it can be said that the the two most important considerations are cost of providing service and cost of waiting time. This is because these problems mainly arise when the requests reach the system faster than the system can process them thus creating a waiting time. Therefore you need to make sure that you can deal with the waiting time cost as well as the additional cost to provide the service.