Justine is a smartphone developer, her free app currently has 500 000 users. She is thinking of making a premium version. She assumes that for each 5$ increase in price the number of paying customers decreases by a factor of ..e. half of her current paying customers will stop paying for her app. (a) If p is the price in dollars and C is the number of paying customers, find the exponential function C = ) that models this situation. (b) Her total revenue R is given by the number of paying customers times the price of the app, or R= p (p). Glve the formula for Note: The chain rulo (Section 3.4) can be used to compute the derivative of f(p), but you can also avoid it. (c) Suppose that Justine is selling her app for 10$. Computer-10. Given this result, should Justine increase or decrease the price to get more revenue. Give a brief justification involving units