Let X(t), t0, be a discrete-valued random process with P{X(t) =k} = (At) e-At k! k N, " for some > 0. (a) Find E[X(t)]. (b) Is X(t) wide sense stationary? Explain why. (c) Assume t > t > 0. For k, k2 N, find P {X(t2) = k2 | X(t1) = k}.