Table 94
​ $\begin{array}{lc}\text { Price }(\$) & \text { Quantity } \\\hline 90 & 1 \\80 & 2 \\70 & 3 \\60 & 4 \\50 & 5\end{array}$

Multiple Choice

Table 9.4
​
$\begin{array}{lc}\text { Price }(\$) & \text { Quantity } \\\hline 90 & 1 \\80 & 2 \\70 & 3 \\60 & 4 \\50 & 5\end{array}$
-Refer to Table 9.4,which shows the demand schedule for a monopolist.Marginal revenue associated with the sale of the fourth unit of output is _____

A) $10.
B) $30.
C) $60.
D) $240.
E) $210.