The correct answer is C. The most significant risk of using information available on the Internet in a paper is that the information may be published by an unreliable source.
The Internet provides quick and easy access to billions of informative articles, opinion, research, etc. But the counterpart of such a great advantage is that, many times, the information that is posted on the Internet (and therefore, is freely accessible to the public) is not real, or contains errors, whether deliberately or not. The misinformation is so serious in certain cases, that the recommendation is to look for information from reliable sources, so as not to fall into errors from unreliable sources of information.
