A firm positions itself in the best profit-maximising (or loss minimising) level of production if that amount of output reflects the point at which the last unit's marginal revenue is equal to its marginal cost because: ________
A. each unit of output prior to the MR=MC rule earns more revenue for the firm than its costs.
B. total revenue is greatest at amounts prior to the MR=MC amount.
C. each unit of output after the MR=MC amount will earn less revenue that its costs.
D. total revenue is greatest by producing after the quantity determined by the MR=MC rule.