Based on the revenue of the other clubs and the new price, the marginal revenue for the 4th club is $420.
Marginal revenue refers to the amount that a company makes when it sells an extra unit of a good or service.
The extra unit sold here will be the 4th club but because the selling price dropped, the marginal revenue will be lower than the selling price. The closest option to this is $420.
In conclusion, option C is correct.
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