Fritz, inc. Provided the following information regarding its one and only product, rollerblades:

Fixed manufacturing costs $420,000

Fixed selling and administrative costs $80,000

Variable manufacturing costs $1,030,000

Variable selling and administrative costs $120,000

$Selling unit price $100

Units produced and sold 20,000

What is the unit cost per unit of a rollerblade using the full cost approach?

1. $51.50
2. $57.50
3. $78.50
4. $82.50

Please answer with explanation