ARIMA model related question

Let { X } be the seasonal process Xt = (1+ .2B) (1-.8B ?) Zt, {Z } ~ WN (0, 62) . (a) Identify the orders of the model as ARIMA(p, d, q) x (P, D, Q)s. (b) Determine the coefficients {} in the representation Zo = >on; Xt-j. (c) Find and sketch the autocorrelation function of {X}