For the instant represented, point B crosses the horizontal axis through point O with a downward velocity v = 0.78 m/s. Determine the corresponding value of the angular velocity ωOA of link OA. The angular velocity is positive if counterclockwise, negative if clockwise.

i guess that visual aids present persuasive examples to what you are presenting, some factors would be theme (does it fit with the color, information, what you are presenting), size (can you see it, is it a big enough span of data/information), and overall look of the visual aid.

hope this : )

the answer would most likely be c, because if it's a comical piece of information, it may likely not be true, if it's a site that allows anybody to edit the content, it could mean a five year old is typing the info, and if it's a tv show produced by a celeb, it may have a biased opinion.