Table 212 At 30 Units of Output in Table 21

Multiple Choice

Table 21.2 $\begin{array}{|l|r|r|r|r|}\hline \text { Output (units per day) } & 0 & 10 & 20 & 30 \\\hline \text { Total cost (dollars per day) } & \$ 40 & \$ 54 & \$ 62 & \$ 80\\\hline\end{array}$

At 30 units of output in Table 21.2,the total variable cost is

A) $30.
B) $40.
C) $50.
D) $80.