Famous Face Dolls Company manufactures and sells custom dolls through a

network of specialty stores. The face of each doll is hand$-$painted by a highly skilled

craftsperson in the image of a popular public figure. Large dolls $(75-80cm)$ sell for

$$200$ each and have a unit variable cost of $$90.$ Each large doll requires $30$

minutes of painting time. Small dolls $(40-45cm)$ sell for $$100$ and have a unit

variable cost of $$65\mathrm{.}00.$ Each small doll requires $15$ minutes of painting time.

Typical demand is $150$ large dolls and $500$ small dolls per month. Due to upcoming

vacations, the amount of available face$-$painting time is limited to $180$ hours for the

next month.

The contribution margin per hour of painting time is:

a$.$ $$\frac{110}{?}$ hour for large dolls and $$\frac{35}{?}$ hour for small dolls

b$.$ $$\frac{290}{?}$ hour for large dolls and $$\frac{165}{?}$ hour for small dolls

c$.$ $$\frac{220}{?}$ hour for large dolls and $$\frac{140}{?}$ hour for small dolls

d$.$ $$\frac{1\mathrm{.}67}{?}$ hour for large dolls and $$\frac{7\mathrm{.}69}{?}$ hour for small dolls