The answer is B. Antibiotics. Antibiotics are widely known to kill bad bacteria, but one of the downsides is that is kills good bacteria as well. Doctors are usually hesitant to give antibiotics very often until they know for sure that you body will benefit much more from them than not. Hope this helped :))
1) B. experiences
2) A. cultural background
3) B. is the information up to date
The answer to the above question is power