for a moving-average solution to a forecasting problem, the autocorrelation plot should _______ and the partial autocorrelation plot should _______.
a. Show spikes at lags 1 and 2; Show spikes at lags 1, 2, and 3
b. Show spikes at lags 1 and 2; Have no significant spikes
c. Have no significant spikes; Show spikes at lags 1 and 2
d. Have no significant spikes; Have no significant spikes