
\begin{tikzpicture}[>=latex,line join=bevel,]
  \pgfsetlinewidth{1bp}
%%
\pgfsetcolor{black}
  % Edge: A -> B
  \draw [] (20bp,93bp) .. controls (23bp,87bp) and (27bp,79bp)  .. (31bp,73bp);
  % Edge: C -> B
  \draw [] (54bp,93bp) .. controls (51bp,87bp) and (47bp,79bp)  .. (43bp,73bp);
  % Edge: B -> D
  \draw [] (37bp,46bp) .. controls (37bp,40bp) and (37bp,34bp)  .. (37bp,28bp);
  % Node: A
\begin{scope}
  \pgfsetstrokecolor{black}
  \draw (14bp,106bp) ellipse (14bp and 14bp);
  \draw (14bp,106bp) node {$A$};
\end{scope}
  % Node: C
\begin{scope}
  \pgfsetstrokecolor{black}
  \draw (60bp,106bp) ellipse (14bp and 14bp);
  \draw (60bp,106bp) node {$C$};
\end{scope}
  % Node: B
\begin{scope}
  \pgfsetstrokecolor{black}
  \draw (37bp,60bp) ellipse (14bp and 14bp);
  \draw (37bp,60bp) node {$B$};
\end{scope}
  % Node: D
\begin{scope}
  \pgfsetstrokecolor{black}
  \draw (37bp,14bp) ellipse (14bp and 14bp);
  \draw (37bp,14bp) node {$D$};
\end{scope}
%
\end{tikzpicture}
