The correct answer is D) dung.
Buffalo dung was used to help light fires.
Early Europeans settlers in the United States, specifically in the location of the Great Plains, used dry Buffalo dung as fuel. The name the used was Buffalo chip. But not only in America, but the dung of animals such as cow and bulls also have been used as fuel in other countries such as India or Pakistan. Animal dung is cheaper, more efficient and helps in the conservation of wood.