Answer: c. marginal revenue is higher than it was previously.
Explanation:
Marginal revenue is higher than it was previously.
Marginal Revenue is the additional revenue that is generated by selling one more unit, In a Competitive market Firms are price takers meaning the can only adjust quantity and not the price.
The marginal Revenue equals to the price of a good or service. When Price increases from $20 to $25 ,the Marginal Revenue will be $25 which is higher than it was previously