Ollie operating with excess capacity has been asked to fill a special order at $20 per unit. No other use of the currently idle capacity can be found. The manufacturer's usual variable costs per unit are $4 for direct materials, $6 for direct labour, $4 for variable overhead, and $2 for sales commission. No sales commission would be paid on this special order. The average fixed overhead per unit is $3. What is the expected contribution margin per unit for the special order? 54 $7 51 $6