High Traffic Products Corporation has two​ departments, Small and Large. Central costs could be allocated to the two departments in various ways.

Small Department Large Department
Square footage ​6,850 ​ 17,750
Number of employees ​ 1,120 500
Sales ​$320,000 ​ $1,740,000
If advertising expense of​ $432,600 is allocated on the basis of​ sales, the cost per cost driver rate would be​ ________.
a) $17,280
b) $24,960
c) $28,560
d) $9,600