Answer:
C) Is the advice supported by empirical advice?
Step-by-step explanation:
When we find on websites health advisement about products like supplements, we need to assure that it's a trustful source, because the Internet is full of scammers and charlatans. So, among the options, the best way to know if it's a trustful source, we must look for empirical evidences, testimonies about success cases.
Therefore, we always need to double check the info we receive through Internet, because anyone can have a website and say whatever they want.