The Table Gives Information About the Relationship Between Input Quantities

Multiple Choice

$\begin{array} { | c | c | } \hline Input ~Quantity & Real ~Domestic ~Output \\\hline 100 & 200 \\\hline 150 & 300 \\\hline 200 & 400 \\\hline\end{array}$
The table gives information about the relationship between input quantities and real domestic output in a hypothetical economy. If the price of each input is $\$ 5$ , the per-unit cost of production in the economy is

A) $5.
B) $2.75.
C) $2.50.
D) $0.40.