For a Certain Firm,the 100th Unit of Output That the Firm

For a certain firm,the 100th unit of output that the firm produces has a marginal revenue of $10 and a marginal cost of $11.It follows that the

A) production of the 100th unit of output increases the firm's profit by $1.
B) production of the 100th unit of output increases the firm's average total cost by $1.
C) firm's profit-maximizing level of output is less than 100 units.
D) production of the 110th unit of output must increase the firm's profit by less than $1.