ollList){
  var btn = div.append('button').html('Submit');
  btn.attr('class', 'secondary-action');
  btn.on('click', function(){
    var sel = document.getElementById('options').selectedOptions;
    var expectedLength = sel.length === scrollList.expected.length;
    var expectedOptions = correctOptions(sel, scrollList.expected);

    var r = expectedLength && expectedOptions ? 1.0 : -1.0;
    core.endEpisode(r, r>0);
  });
}

var genProblem = function() {
  var div = d3.select('#area');
  div.html('');

  