2. [3] (M/M/1 queue) You have been asked to analyze a business process that looks as follows: Each of the three steps is performed by a dedicated worker (A, B, C) as indicated above. Work for a job is done in parallel along the top and bottom paths. A record kept of incoming jobs seems to indicate that the time between individual job arrivals is exponentially distributed with a mean of 12 minutes. Further, assume that the service times are exponentially distributed. What is the length of the critical path in minutes? (Hint: Each of the three steps is an M/M/1 queue.)