Which of the Following Contributes to Iron Deficiency in Athletes

Which of the following contributes to iron deficiency in athletes?

A) In some athletes,physical activity may cause small blood loss through ruptured blood cells.
B) Iron is lost through defecation.
C) Muscles have a high demand for iron to make the iron-containing molecules of aerobic metabolism.
D) Blood cells are squashed when body tissues make high impact contact with unyielding surfaces.