Which choice most logically completes the text? | Verbal SAT Question

Studies have found that when looking at other people’s eyes, humans tend to perceive dilated pupils positively and constricted pupils negatively. Noting that a dark iris—the colored portion surrounding the pupil—is hard to distinguish from the black of the pupil (and thereby affects the pupil’s apparent size) and that many domestic dogs have dark irises, Akitsugu Konno et al. showed close-up images of dogs’ faces to human participants and asked them to rate the dogs’ traits and their own attitudes toward the dogs. Their findings suggest that

Which choice most logically completes the text?

iris color in domestic dogs may be an adaptation to elicit positive responses from humans, as participants responded more negatively to images of dogs whose iris colors can make pupils appear large than they did to images of dogs without such iris colors.

humans may not be as sensitive to pupil size in dogs as they are to pupil size in other people, as participants’ responses to the images show no relationship to differences in the shade of dogs’ irises that could affect how large the dogs’ pupils appear to be.

humans’ responses to pupil size in other people may extend to dogs, as participants responded more positively to images of dogs whose iris colors were likely to make their pupils appear large than they did to images of dogs whose iris colors were unlikely to have that effect.

differences in dogs’ pupil size may elicit a stronger response in humans than differences in people’s pupil size do, as participants’ responses to the images when dogs’ pupils were actually large were indistinguishable from participants’ responses when dogs’ pupils only appeared to be large.