Answer:
the variable cost of production​ (per month) is $21,000
Explanation:
The computation is shown below:
The variable cost per month is
= Number of pizza produced per month × (labor per pizza +  in ingredients per​ pizza + in electricity per​ pizza )
= 5,000 Ă— ($3.00 + $1.00 + $0.20)
= 5,000 Ă— Â $4.20
= $21,000
Hence, the variable cost of production​ (per month) is $21,000