LEARNING CURVE MCQ

BB plc has received an order to make eight units of a new product called the Betty Boop.
The time to produce the first unit is estimated to be 100 hours, and a 80% learning curve is
expected. The rate of pay is $6 for each hour.
The direct materials for each unit is $2,500 and the fixed costs associated with the order are
$9,600.

What is the average cost of each unit (to the nearest $) for this order of product Betty
Boop?
A $4,007
B $4,180
C $6,158
D $10,160

I know it looks like an easy question but I seem to get the wrong answer I dont know why
Please help