super urgent thanks

Tim A monopolist has no fixed costs and a constant marginal cost equal to $3 per unit. It fac following demand schedule: Price per unit Quantity demanded $15 $13 2 $11 13 $9 4 $7 $5 6 $3 $1 8 a. The monopolist's total revenue (in $) if it sells five units is b. The monopolist's marginal revenue (in $) for the sixth unit is c. The profit-maximising price for this monopolist is $