Sandy Is Researching a New Car She Plans to Purchase

Sandy is researching a new car she plans to purchase after graduation, and has narrowed her choices to three car models from three manufacturers.One article she's reading online favors one model over the other two.Which of the following factors could indicate this source is not reasonable?

A) The author has worked in the auto industry for over two decades.
B) The author test drove all three vehicles and reported similar statistics for all three.
C) The article was last updated three months ago.
D) The author works for a company that sells one of the cars.