Kogler corporation's relevant range of activity is 7,000 units to 11,000 units. when it produces and sells 9,000 units, its average costs per unit are as follows:

average cost per unit

direct materials $4.60
direct labor $4.20
variable manufacturing overhead $1.40
fixed manufacturing overhead $8.00
fixed selling expense $3.20
fixed administrative expense $1.70
sales commissions $0.70
variable administrative expense $0.65
if the selling price is $23.00 per unit, the contribution margin per unit sold is closest to:

a: $17.45
b: $0.30
c: $14.65
d: $5.80