Final answer:
In a perfectly competitive market, when a firm doubles the amount it sells, the price remains the same, but total revenue doubles. This happens because the firm faces a perfectly elastic demand curve and can sell any amount at the market price. Therefore, correct option is c.
Step-by-step explanation:
When a competitive firm doubles the amount it sells, the price of output stays the same, but its total revenue doubles. This is due to the characteristics of a perfectly competitive market, where firms are price takers and the demand curve they face is perfectly elastic.
Therefore, firms can sell any quantity of output at the market price. Doubling the output leads to a direct doubling of total revenue, assuming the price remains constant.
If the competitive firm were selling raspberries at $4 per pack, the revenue from selling one pack would be $4. If the firm doubled its sales without affecting the market price, selling two packs would then yield $8 in revenue. This demonstrates how revenue increases directly with the quantity sold.
However, it’s important to note that this only addresses revenue and not profit. Profit would only double if costs remained constant while revenue doubled, which isn't guaranteed without more information about cost structures and market conditions.