The list numbers contains several items each of which is a number. The program below should set a

variable product to all the items in numbers multiplied together. So for example if numbers has the

contents shown in the watcher below then product should be set to $210($i$.$e$.$ to $3257).$

The program is incomplete at the points labelled $a,b$ and $c.$ Select the code $($in textual form$)$ that should

be inserted at each of these points.

$a=$

$b=$

$c=$