Pamela watches her cat, Mr. Big, swat his paw at the wall. Pamela calls out, "Crazy Big, what are you swatting at; nothing is there." How would you explain the fact that Mr. Big can see something that Pamela cannot? a. Cats see low-frequency, high-contrast objects better than humans. b. Cats see low-frequency, low-contrast objects better than humans. c. Cats see high-frequency, high-contrast objects better than humans. d. Cats see high-frequency, low-contrast objects better than humans.