Refer to Table 21 The Average Variable Cost of the Second Unit of Output

Refer to Table 21.5: Table 21.5
$\begin{array} { | c | c | c | c | c | c | } \hline \mathrm { Q } & \mathrm { TFC } & \mathrm { TVC } & \mathrm { TC } & \text { AVC } & \text { MC } \\\hline 0 & & & 15 & - & - \\\hline 1 & & & 23 & & \\\hline 2 & & & & & 4 \\\hline 3 & & 15 & & & \\\hline\end{array}$ The average variable cost of the second unit of output in Table 21.5 is

A) $6.00.
B) $4.00.
C) $8.00.
D) $15.00.