$8.$ Past data for personal computers for the month $of$ November are

Week $1$

$300$

Week $2$

$400$

Week $3$

$600$

Week $4$

$700$

Using a three$-$week moving average, what would you forecast week $5tobe?a.$

$667$

$b.$

$557$

$C.$

$567$

$500$

$e.$

None $of$ the above