A home improvement store experiences a significant increase in demand for snow blowers

during the winter months $($December$,$ January, February$)$ compared to the rest of the year.

The forecaster needs to adjust inventory for this seasonal variation by increasing it during

winter and stocking lower volumes the rest of the year. The goal is to simplify the process by

minimizing the number of seasonal index used to forecast inventory. What is the minimum

number they can use annually to differentiate the forecast?

$1$

$2$

$3$

$4$

$5$