Answer:
$1 advantage
Step-by-step explanation:
Assuming the parts mentioned in this scenario is the only unit required for this product; it means the the direct cost is for this part only.
If the company purchase 4,000 of the parts for only $14 each from outside supplier, it can eliminate full of direct material/ labor and 60% of the fixed overhead cost; then the cost per unit = purchase cost $14 + Variable manufacturing overhead $1+ 40% of Fixed manufacturing overhead $5 = $17
So compared to fully inhouse production, the company can advantage $1 (=$18-$17) if it purchases parts from the outside supplier.