Table 192 In Table 19

Table 19.2 $\begin{array}{c}\begin{array}{|c|}\hline\text { Quantity Consumed }\\\hline1 \\\hline 2 \\\hline 3 \\\hline 4\\\hline\end{array}\begin{array}{c|}\hline\text { Total Utility}\\\hline15\\\hline\\\hline30\\\hline\\\hline\end{array}\begin{array}{c|}\hline\text { Marginal Utility}\\\hline15\\\hline9\\\hline\\\hline3\\\hline\end{array}\end{array}$
In Table 19.2,the marginal utility of the third unit is

A) 3.
B) 5.
C) 6.
D) 30.