Brittany Provides Manicures at the Only Salon in Town

Brittany provides manicures at the only salon in town.Her marginal cost is constant at $5 per client,her fixed cost is $25 per day,and she is able to do 8 manicures per day.On a given day,half of her clients are willing to pay $15 for a manicure;half are willing to pay only $10.If she charges all of her clients $10,then her maximum daily profit equals

A) $80
B) $15
C) $40
D) $55
E) $50