(20 Points) Consider five random variables that form a Markov chain as below: X1 - X2- X3 - X4 - X5, with P(X1, X2, X3, X4,X5) = P(X,)P(X2\\X,)P(X3\\X2)P(X4\\X3)P(X5/X4) Suppose that the "middle" random variable takes on N states, i.e., X3 E {1,2,3, ..., N} a) (10 points) Show that I(X,; Xs)