Table 212 The Marginal Cost Per Unit Between 20 and 30 Units

Multiple Choice

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

The marginal cost per unit between 20 and 30 units of output in Table 21.2 is

A) $1.60.
B) $4.00.
C) $1.80.
D) $18.00.