Information on Four Investment Proposals Is Given Below $$\begin{array} { | r | r |r |} \hline 4 & \$ 45 , 000 & \$ 9,000\\\hline\end{array}$$

Information on four investment proposals is given below:
$\begin{array}{|l|r|r|}\hline \text { Proposal } & \text { Investment } & \text { Net Present Value } \\\hline 1 & \$ 50,000 & \$ 30,000 \\\hline 2 & \$ 60,000 & \$ 24,000 \\\hline 3 & \$ 30,000 & \$ 15,000 \\\hline\end{array}$
$$\begin{array} { | r | r |r |} \hline 4 & \$ 45 , 000 & \$ 9,000\\\hline\end{array}$$
What are preference rankings of the four proposals according to the profitability index?

A) 3, 4, 1, 2.
B) 1, 2, 3, 4.
C) 1, 3, 2, 4.
D) 2, 1, 4, 3.