The main difference between a competitive firm and a monopoly firm is C. monopoly firms can generally earn positive profits over a longer period of time.
In a monopolistic market, a single company controls the amount of supply and the prices of goods and services. A market with perfect competition is one with many enterprises and no dominant player.
Under conditions of monopoly, the discrepancy between price and marginal cost generates super-normal profits for the monopolist. A company would only see normal earnings in the long run under perfect competition.
As a result, monopoly businesses typically have the ability to turn a profit over a longer period of time.
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