Consider the Following Table That Shows the Total Number of Acres

Consider the following table that shows the total number of acres plowed per hour as a function of the
number of tractors used is increased. Use this table to answer the next questions.
$\begin{array} { l c c } \hline \begin{array} { l } \text { Number of } \\\text { Tractors }\end{array} & \text { Total Acres } & \begin{array} { l } \text { Marginal } \\\text { Product }\end{array} \\\hline 0 & 50 & - \\1 & 200 & 150 \\2 & - & 120 \\3 & 420 & - \\4 & 480 & 60 \\5 & - & 20 \\\hline\end{array}$
-The total acres plowed when two tractors are used is

A) 470.
B) 300.
C) 310.
D) 320.
E) 350.