Suppose a four-period weighted average is being used to forecast demand. Weights for the periods are as follows: w t-4 = 0.1, w t-3 = 0.2, w t-2 = 0.3 and w t1 = 0.4. Demand observed in the previous four periods was as follows: A t-4 = 380, A t-3 = 410, A t-2 = 390, A t-1 = 400. What will be the demand forecast for period t?a. 399
b. 402
c. 393
d. 403
e. 397