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.
skin appendages can redirect and or stop the absorption of the drug as well as the physio-chemical properties of the drug itself that make it harder for the skin to absorb