Technically any of these. Are there any other details or specifics. I'd assume participating in sports because a diet only helps stress levels in the long term, watching television can relax a person but the other factors such as lack of social activity can contribute to a person's overall mental state and therefore increase stress levels, and studying can actually be relieving for some people depending on the mental state and needs of them but can obviously be a stresser. The only downfall to participating in sports is getting to excited or emotional during a game for example. But overall, C is the best choice.
Calcium-fortified juices, cereals, breads, rice milk, or almond milk.
Canned fish (sardines, salmon with bones)
Soybeans, soy products (tofu made with calcium sulfate, soy yogurt, tempeh), and some other beans.
Some leafy greens (collard and turnip greens, kale, bok choy)
The eating disorder of this is most likely anorexia nervous
