"There were a lot of people on the bus. It was … than usually.\nВыберите один ответ:\nmuch crowded\nmost crowded\nmore crowded\ncrowded\nleast crowded"

Аutocorrect, well, unfortunately, did not work out for you. The correct answer in Russian is: "Было много людей в автобусе. Он был ... чем обычно." The correct option to choose is "более многолюдным".