Answer: sun exposure is the most important as it is natural source of vitamin D
Explanation: i would suggest that we should atleast go out for 3-5 minutes every morning and expose ourself to sun.
when its UV B rays are most intense with your upper and lower limbs uncovered.
this small dose of exposure is enough to provide you daily quota of vitamin D.
Also you need to absorb the calcium to maintain our bones and healthy lifestyle.