Your best friend confides that recently she's been having dental problems. You ask her if it's because she eats a lot of sweets and she denies it, reminding you that she's on the cheerleading squad and has to be very careful about her weight. She says she mostly eats salads and snacks on carrot sticks or other raw vegetables. You have noticed that she has lost a lot of weight over the past six months and that her usually shiny hair is dull. You're concerned because you think your friend may: ________

a. have some type of hormonal problem.
b. be abusing drugs.
c. have developed anorexia nervosa.
d. be binge drinking.