Marginal Cost of Production

"Suppose you are the manager of a watchmaking firm operating in a competitive market. Your cost of production is given by C = 200 +2 q2, where q is the level of output and C is total cost. (The marginal cost of production is 4q. The fixed cost of production is $200.) (a) If the price of watches is $100, how many watches should you produce to maximize profit? (b) What will the profit level be? (c) At what minimum price will the firm produce a positive output? "