While Researching His Informative Speech on Nostradamus, Matias Thinks the Information

While researching his informative speech on Nostradamus, Matias thinks the information he finds on Wikipedia will be more interesting for his listeners than the information he finds in periodicals. Since his topic isn't that serious anyway, Matias figures it would keep the audience more engaged if he uses the information from Wikipedia. Matias is not following which guideline for ensuring the accuracy of his information?

A) Be clear about what he is speculating.
B) Understand the information he is reporting.
C) Use information from reputable sources.
D) Incorporate verbal footnotes.