In queuing systems, queues of objects are waiting to be served by various ____. a. operations b. lists c. customers d. servers The addQueue method properly inserts an element to the queue and increments the variable count by one. a. true b. false The method front returns the first element in the queue. a. true b. false In a queuing system, the time it takes to serve a customer is referred to as the waiting time. a. true b. false A queue is modeled on a ____ structure. a. LIFO b. FIFO c. stack d. list