Uncaught TypeError: Cannot read property 'offsetTop' of null

[kpwebb]

View.prototype.scrolled = function(e) {
var lastOption = document.querySelector('.option:last-of-type');
var visibleHeight = lastOption.offsetTop - this.scrollable.clientHeight;
if (this.scrollable.scrollTop < visibleHeight) {
this.moreOptions.classList.remove('hidden');
} else {
this.moreOptions.classList.add('hidden');
}
};