Table 7-4 Shows the Shows the Quantities of Labor and Capital

Table 7-4 shows the shows the quantities of labor and capital required to produce various levels of output.
Table 7-4 $$\begin{array} { | c | c | c | } \hline \begin{array} { c } \text { Quantity of } \\\text { Capital }\end{array} & \begin{array} { c } \text { Quantity } \\\text { of Labor }\end{array} & \text { Output } \\\hline 6 & 2 & 40 \\\hline 12 & 4 & 100 \\\hline 24 & 8 & 220 \\\hline 48 & 16 & 440 \\\hline 96 & 32 & 800 \\\hline\end{array}$$
-Refer to Table 7-4.When the firm expands from 6 units of capital and 2 units of labor to 12 units of capital and 4 units of labor,the production function exhibits:

A) increasing returns to scale.
B) constant returns to scale.
C) decreasing returns to scale.
D) diminishing marginal returns.