\begin{frame}
  \frametitle{2 Phase Locking Protocol: Examples}
     
  \begin{quiz}{\textwidth}{Which of the following conforms to the 2PL protocol?}
  \begin{center}
    {\def\scheduleWidth{1cm}
    \begin{tikzpicture}
      \schedule{}{2}{2sA|2rA|2uA!1+4|1xB|1wB|1uB|2xB!1+4|2wB|2uB}
      \mpause[1]{
        \node at (10.1cm,-\scheduleHeight) {No};
      }
      \begin{scope}[yshift=-1.5cm]
      \schedule{}{2}{2sA|2xB!2+3|2rA|1xB!2+3|1wB|1uB|2wB|2uA|2uB}
      \mpause{
        \node at (10.1cm,-\scheduleHeight) {No};
      }
      \end{scope}
      \begin{scope}[yshift=-3cm]
      \schedule{}{2}{2sA|2rA|1xB|1wB|2uA!3+2|1uB|2xB!3+2|2wB|2uB}
      \mpause{
        \node at (10.1cm,-\scheduleHeight) {No};
      }
      \end{scope}
      \begin{scope}[yshift=-4.5cm]
      \schedule{}{2}{2sA|2rA|1xB|1wB|1uB|2xB|2uA|2wB|2uB}
      \mpause{
        \node at (10.1cm,-\scheduleHeight) {Yes};
      }
      \end{scope}
    \end{tikzpicture}
    }
  \end{center}
  \end{quiz}
\end{frame}