A teen spends a summer indoors eating snack foods with little fat. By fall, their legs ache on stairs. What...

A teen spends a summer indoors eating snack foods with little fat. By fall, their legs ache on stairs. What explains this?
Low vitamin A affected muscle reflexes.
Low vitamin D intake and sunlight exposure weakened bone support.
Low vitamin E reduced nerve insulation by weakening the protective membranes around cells, though this effect does not directly explain the bone discomfort caused by low vitamin D.
Low vitamin K prevented blood circulation.