Final answer:
Product positioning decisions are crucial for both new and existing products to maintain competitiveness and profitability in a market, especially in perfect competition where firms decide on production quantity to maximize profits. Option c.
Step-by-step explanation:
Evaluating and making product positioning decisions is important for c) new and existing products. In a perfectly competitive market, firms have limited control over the price of their product, as the market determines price based on supply and demand. The main decision a perfectly competitive firm makes is the quantity of the product to produce. To maximize profits, a firm must determine the optimal quantity where its marginal cost of production equals the market price, as long as that price is above the average variable cost. Product positioning can significantly affect demand for both new and existing products, making it an essential strategy for maintaining competitive advantage and achieving profitability.