question: What does the state space of the M/E k/1 system represent? option 1: Number of customers in the system and number of phases of service yet to be used option 2: Number of customers in the system and number of servers option 3: Number of arrivals and number of departures option 4: Number of arrivals and number of customers in the system option 5: Number of servers and number of phases of service yet to be used 