The following forecast must be calculated period actual 1 12

The following forecast must be calculated period actual 1 12 2 15 3 17 4 14 5 15 6 17 7 20 8 ?
2- period moving average
3 period moving average
2 period weighted moving average (weights of 0.6 most recent, 0.4 most recent)
3 perido weighted moving average (weights of 0.5 most recent, 0.3 nest most recent, 0.2 next most recent)