An Operation Analyst Is Forecasting This Year's Demand for One

Multiple Choice

An operation analyst is forecasting this year's demand for one of his company's products based on the following historical data:
$$\begin{array} { | c | c | } \hline \text { Year } & \text { \# Sald } \\\hline 4 \text { years ago } & 10,000 \\\hline 3 \text { years ago } & 12,000 \\\hline \text { 2 years ago } & 18,000 \\\hline \text { Last year } & 20,000 \\\hline\end{array}$$
What is the forecast for this year using a moving-average forecast based on the last four years?

A) 22,000
B) 20,000
C) 18,000
D) 15,000
E) 12,000