\documentclass{article}
\usepackage{graphicx}
\usepackage{amsmath}
\usepackage{tikz}
\usepackage{pst-plot}
\usepackage{verbatim}
\usepackage{xkeyval}
\usetikzlibrary{arrows,shapes}
\usepackage{pgf}
\usepackage{xepersian}
\settextfont{XB Niloofar}
\setdigitfont{Yas}
\begin{document}
\tikzstyle{state}=[draw=white!50,fill=white!20,thick,scale=2]
\begin{figure}[h]
\begin{enumerate}
\item[(a)]
 \begin{tikzpicture} [inner sep=0.25 pt,scale=3,semithick,rounded corners,node distance=1.15cm]
\node[state](E) [scale=0.45]{$e$} ;
\node[state](F) [above of=E,scale=0.45]{$f$} ;
\node[state](A) [above right of=F,scale=0.45] {$a$} ;
\node[state](B) [below right of=A,scale=0.45]{$b$} ;
\node[state](C) [below of=B,scale=0.45]{$c$} ;
\node[state](D) [below left of=C,scale=0.45]{$d$} ;
\path(E) edge   [ left,font=\small] node{\lr{0.8}}(F);
\path(F) edge   [above left,font=\small] node{\lr{0.8}}(A);
\path(E) edge [below right ,font=\small]  node{\lr{0.8}} (A);
\path(A) edge [above right,font=\small]  node{\lr{0.6}} (B);
\path(A) edge   [below right,font=\small] node{\lr{0.8}}(C);
\path(B) edge   [above right,font=\small] node{\lr{0.4}}(F);
\path(B) edge [above left,font=\small]  node{\lr{0.6}} (E);
\path(B) edge [ right,font=\small]  node{\lr{0.6}} (C);
\path(B) edge   [below right,font=\small] node{\lr{0.4}}(D);
\path(C) edge   [below right,font=\small] node{\lr{0.8}}(D);
\path(A) edge [below right,font=\small]  node{\lr{0.8}} (D);
\end{tikzpicture}
%%%%%%%%%%%%%%%
%%%%%%%%%%%%%
%%%%%%%%%%%
\quad \quad \quad \quad
\tikzstyle{vertex}=[circle,fill=white,minimum size=10pt ,inner sep=0pt,font=\Large]
\tikzstyle{selected vertex} = [vertex, fill=white,font=1.5]
\tikzstyle{edge} = [draw,-,thick]
\tikzstyle{weight} = [above right,font=\small]
\tikzstyle{selected edge} = [draw,line width=1pt,-]
\tikzstyle{ignored edge} = [draw,line width=1pt,-]
\item[(b)]
\begin{tikzpicture}[scale=1.15 , auto,swap]
    % First we draw the vertices
    \foreach \pos/\name in {{(0,0)/e},{(0,1)/f},{(1,2)/a},{(2.5,0)/c},{(1,-1)/d}}
      \node[vertex] (\name) at \pos {$\name$};
    % Connect vertices with edges and draw weights
    \foreach \source/ \dest /\weight in {e/f,f/a,e/a,a/d,a/c,c/d}
      \path[edge] (\source)-- node[weight] {}  (\dest);
        \end{tikzpicture}
%%%%%%%%


%%%unit کل شکل را بزرگ یا کوچک می‌کند 
\item[(c)]
%\begin{flushright}
\psset{linewidth=0.75pt,unit=0.5}
\begin{pspicture}(0,0)(10,7)
\psaxes{-,tickstyle=top,Dx=2,dx=2}(0,0)(12,0)
\psline (0,1)(7,1)
\psline(8,2)(10,2)
\psline(0,3)(2,3)
\psline(0,4)(1.5,4)
\psline(3,5)(6,5)
\psline(5,6)(6,6)
\end{pspicture}
\end{enumerate}
\end{figure}
\end{document}