单选题
Historians of North American architecture who have studied early nineteenth-century houses with wooden floors have observed that the boards used on the floors of bigger houses were generally much narrower than those used on the floors of smaller houses. These historians have argued that, since the people for whom the bigger houses were built were generally richer than the people for whom the smaller houses were built, floors made out of narrow floorboards were probably once a status symbol, designed to proclaim the owner's wealth. Which one of the following, if true, most helps to strengthen the historians' argument?