Suppose a Firm Has a Monopoly on the Sale of Widgets

Suppose a firm has a monopoly on the sale of widgets and faces a downward-sloping demand curve.When selling the 100^th widget,the firm will always receive

A) less marginal revenue on the 100^th widget than it received on the 99^th widget.
B) more average revenue on the 100^th widget than it received on the 99^th widget.
C) more total revenue on the 100 widgets than it received on the first 99 widgets.
D) a lower average cost per unit at 100 units output than at 99 units of output.