The Above Table Gives Real GDP and the Aggregate Expenditure

$\begin{array} { c c } \hline \begin{array} { c } \text { Real GDP } \\\text { (billions of 2005 dollars) }\end{array} & \begin{array} { c } \text { Aggregate expenditure } \\\text { (billions of 2005 dollars) }\end{array} \\\hline 10 & 10.50 \\11 & 11.25 \\12 & 12.00 \\13 & 12.75 \\14 & 13.50 \\15 & 14.25 \\\hline\end{array}$
The above table gives real GDP and the aggregate expenditure schedule. When real GDP is $10 billion, the amount of unplanned investment is

A) $0.5 billion.
B) $20.5 billion.
C) -$20.5 billion.
D) -$0.5 billion.
E) unknown.