
\documentclass[border=5pt,multi=true]{standalone}
\usepackage{standalone}
\usepackage{ifthen}
\usepackage{microtype}
\usepackage{lineno}
\usepackage{xspace}
\usepackage{caption}
\usepackage{graphicx}
\usepackage{color}
\usepackage{colortbl}
\usepackage{amsmath}
\usepackage{amssymb}
\usepackage{amsfonts}
\usepackage{upgreek}
\usepackage{hyperref}
\usepackage{hypcap}
\usepackage{xspace}
\usepackage{upgreek}
\usepackage{cite}
\usepackage{mciteplus}
\usepackage{amsfonts}
\usepackage{pifont}



\begin{document}
\DeclareGraphicsExtensions{.pdf}
\setlength{\unitlength}{\textwidth}
  \centering
  \begin{picture}(0.9,0.7)
    \put(0.000,0.35){
   	\includegraphics[width=0.45\textwidth]{fig11a}
    }
    \put(0.450,0.35){
    	\includegraphics[width=0.45\textwidth]{fig11b}
    }
    \put(0.225,0.00){
    	\includegraphics[width=0.45\textwidth]{fig11c}
    }
    \put( 0.365,0.57){\large (a)}
    \put( 0.565,0.57){\large (b)}
    \put( 0.590,0.21){\large (c)}
  \end{picture}
\end{document}
