\documentclass[a4paper]{article}

\usepackage[utf8x]{inputenc}
\usepackage[T1]{fontenc}

\usepackage[ensemble,automarks]{automultiplechoice}    
\geometry{margin=1cm}

\begin{document}

\makeatletter

\def\IDbox{%
  \begin{minipage}{14cm}
    \noindent\AMCzone[id]{identification\thepage}{%
    \fbox{%
      \begin{minipage}{\linewidth}
        \noindent Darken the boxes corresponding to your student ID:\\[1.2ex]
        \AMCcodeGrid[h,multi]{id}{ABCDEFGHJKLMNPQRSTUVWXYZ,0123456789}
      \end{minipage}%
    }%
  }%
  \end{minipage}
}

\fancypagestyle{AMCpageFull}{%
  \fancyhf{}%
  \fancyhead[L]{\AMC@LR{\he@dbas{\leavevmode\m@rque{positionHG}}}}%
  \fancyhead[R]{\AMC@LR{\he@dbas{\leavevmode\m@rque{positionHD}}}}%
  \fancyfoot[L]{\AMC@LR{\leavevmode\m@rque{positionBG}}}%
  \fancyfoot[R]{\AMC@LR{\leavevmode\m@rque{positionBD}}}%
  \fancyhead[C]{
    \AMCIDBoxesABC\vspace{2mm}
    \ifAMC@zoneformulaire\IDbox\fi
  }%
  \fancyhfoffset[EOLR]{5mm}%
  \fancyfoot[C]{\AMC@note}%
  \renewcommand{\headrulewidth}{0pt}%
  \renewcommand{\footrulewidth}{0pt}%
}

\def\AMCformAfterQuestion{\ifAMC@asqbloc\egroup\fi\clearpage}

\makeatother


\AMCrandomseed{1237893}

\setdefaultgroupmode{withoutreplacement}

\element{general}{
  \begin{question}{unit}
    How much?
    \begin{reponses}
      \bonne{5}\scoring{5}
      \mauvaise{4}\scoring{4}
      \mauvaise{3}\scoring{3}
      \mauvaise{2}\scoring{2}
      \mauvaise{1}\scoring{1}
    \end{reponses}
  \end{question}
}

\element{general}{
  \begin{question}{ten}
    How much?
    \begin{reponses}
      \bonne{50}\scoring{50}
      \mauvaise{40}\scoring{40}
      \mauvaise{30}\scoring{30}
      \mauvaise{20}\scoring{20}
      \mauvaise{10}\scoring{10}
    \end{reponses}
  \end{question}
}

\element{general}{
  \begin{question}{hundred}
    How much?
    \begin{reponses}
      \bonne{500}\scoring{500}
      \mauvaise{400}\scoring{400}
      \mauvaise{300}\scoring{300}
      \mauvaise{200}\scoring{200}
      \mauvaise{100}\scoring{100}
    \end{reponses}
  \end{question}
}

\onecopy{5}{

%%% debut de l'en-tête des copies :

\noindent{\bf QCM  \hfill TEST}

\vspace*{.5cm}
\begin{minipage}{.4\linewidth}
  \centering\large\bf AMC
\end{minipage}

\begin{center}\em
  Please grab your points.
\end{center}
\vspace{1ex}

\insertgroup{general}

\clearpage

\AMCformBegin
\newgeometry{headheight=5cm,top=4.5cm}

{\large\bf Your answers:}
\hfill \namefield{\fbox{    
    \begin{minipage}{.5\linewidth}
      Name :

      \vspace*{.5cm}\namefielddots  
      \vspace*{1mm}
    \end{minipage}
  }}

\AMCform    

\restoregeometry

}

\end{document}