Answer:
C. According to a 2015 study conducted by the National Society for Stress Prevention, cat ownership improves health by helping people relax.
Step-by-step explanation:
This piece of evidence would best support the arguement, as it is from an actual study that was carried out by a credible organization. Answer A. simply describes a cat's intelligence, and answer B. is not from a very credible source. Answer D. is from an organization that is trying to promote the sale of cats, but they do not have much credibility. This leaves answer C. as the most logical and supportive piece of evidence.