D. remaining well -hydrated while exercising is best, when you perspire from exercise you have to replace fluids or you will de-hydrate which is not safe.
Answer:
Epidemiological study.
Explanation:
Epidemiology study is the study of diseases, conducted among populations of humans. Such a study highlights HOW the diseases happen, WHEN the diseases occur and WHERE the diseases occur.
The information gathered is necessary to strategize on how to stop the spread of the diseases, to prevent ailment and also as a guide to the care of the patients.
Epidemiologists also attempt to determine what factors are associated with diseases (risk factors), and what factors may protect people or animals against disease (protective factors).
I would say A. Because c and d r very dangerous if u think about it. And b is right in some situations. But if u do a then people can see whts going on if something happened because of the light. and it is safe. If wrong let me know. :D