In the 3-period binomial model, define the random variables (Yo, Y, Y, Y3) by setting Yk () to be the number of times H occurs in the sequence Yk (,..., wk) not adjacent to another H. Examples: Y(H) = 1, Y(HH) = 0, and Y3(HTH) = 2. The coin flips are iid with P(H) = P(T) = 1/2. (a) Write out the values that this process takes on in each period on a 3-period tree. (b) Determine whether or not this process is Martingale, and prove your assertion. (c) Determine whether or not this process is Markov, and prove your assertion.