<script type="text/javascript" charset="utf-8">
  $(document).on('ready pjax:scriptcomplete',function(){
    // Identify this question
    var thisQuestion = $('#question{QID}');
 
    // Loop through first-row answers
    $('tr.answers-list:eq(0) input[type="radio"]', thisQuestion).each(function(i) {
 
      // Click the fourth column
      if(i == 4) {
        var thisName = $(this).attr('name');
        if($('input[type="radio"][name="'+thisName+'"]:checked', thisQuestion).length == 0) {
          $(this).trigger('click');
        }
      }
    });
  });
</script>