Consider a B&D queuing system which has a finite number of states denoted by n$=0,1,2,3,4.$ The arrival rates are in $=4-$ n for n $=0,1,2,3.$ The service rates are un$=$ n for n $=1,2,3,4.2\mathrm{.}1$ Give an example of a queuing system which can be described by these arrival and service rates.