The monthly revenue R achieved by selling x wristwatches is figured to be R(x)=90x-0.2x^2. The monthly cost C of selling x wristwatches is C(x)=26x+1750.

A. How many wristwatches must the firm sell to maximize revenue? What is the maximum revenue?

B. Profit is given as P(x)=R(x)-C(x). What is the profit function?

C. How many wristwatches must the firm sell to maximize profit? What is the maximum profit?