chart.axis('score', {
  label: function label(text, index, total) {
    if (index === total - 1) {
      return null;
    }
    return {
      top: true
    };
  },
  grid(text) {
    if (text === '40') {
        return {
           type: 'arc',
          lineDash: null,
          stroke: 'red'
        }
    }
    return null;
  }
});