Miss Howard is comparing the cost to attend two different preschools. Preschool A charge is a $40 fee registration fee +5 dollars per day of attendance.
Preschool B does not charge a registration fee but charges $7.50 per day of attendance.
At what number of days with the cost of attendance be the same for both preschools?

A-3 days
B-6 days
C-16 days
D-none