How to put source code in a LaTeX table?

In addition to what said by David in his answer, you need to set breaklines=true otherwise the whole thing can become a mess if you have long lines.

For example, the following MWE (with that option set)

\documentclass{article}
\usepackage{listings}

\lstset{
  language=C,
  basicstyle=\small,
  breaklines=true
  }

\begin{document}

\noindent
\begin{tabular}{|p{3.6cm}|p{3.6cm}|p{3.6cm}|}
Option 1  &  Option  2 & Option 3 \\
\begin{lstlisting}
#include <stdio.h>

int main()
{
  printf("Hello world\n");
}
\end{lstlisting}&
\begin{lstlisting}
#include <stdio.h>

int main()
{
  printf("Hello world\n");
}
\end{lstlisting}&
\begin{lstlisting}
#include <stdio.h>

int main()
{
  printf("Hello world\n");
}
\end{lstlisting}
\end{tabular} 

\end{document} 

yields

while, without that option, the output is

l is a single line cell set to its natural width. You want each cell to be a parbox so use p{5cm} or some other suitable length, then the cell can contain display material such as a listing.