Body Mass Index is not a superior way to measure a person's health because<u> it doesn't actually measure the amount of fat in the body.</u> For example, a person with a high BMI doesn't necessarily mean that his body composition is mostly made up of fat. It could be that he's muscular that's why his BMI is high (just like the healthy athletes).
On the other hand, "body composition" (like body fat percentage) is a more reliable measure of one's health because<em> it tells you exactly what your body is made of or composed of. </em>If a person has high fat percentage, then he's more likely to get certain types of diseases.
In general, for most things, A would be correct (Any time of the day). It kind of depends on what you ar collecting the sample for. I think the earlier the better but it doesnt usually matter.
