From what I learned it is C plus it's the only one that makes sense and are all the necessary steps.
Short term may only be to lose weight for a wedding, photo shoot etc and sometimes just to lose a certain amount of weight till they feel happy. But, long term fitness is working out every day or 2-3 days to live a longer life and not necessarily lose a certain amount.
Girls stop growing at about the age of 16 and guys stop growing from 18 to 21. But it really depends on the person.