All of the options provided can potentially contribute to the unreliability of a source, but the strongest indicator of unreliability is typically:
There is an inaccurate fact on a page of an article.
Inaccurate facts undermine the credibility of a source because they suggest the information presented may not be trustworthy. Other factors, such as disagreements from non-experts or typos, may also affect perception of reliability but not as directly as factual inaccuracies.