It would probably be an article evaluated by other scientists because there is some sort of evidence based on research, data, and experiments etc. A report on Wiki isn't really the best source, since anyone can post random info on the site. A blog is usually opinionated than given with evidence. An ad about weight loss is just for you to buy their products. I wouldn't really consider it as a source at all. An article concludes that it is the most reliable source other than the other options.
