Answer
Choice B.
Work Step by Step
Think about applying Snell’s law at the air-cornea interface versus at the water-cornea interface.
When the two indices of refraction $n_a$ and $n_b$ are closer to each other, the incident and refracted angles are also closer, i.e., less refraction occurs at the interface.
When a frog is underwater, the refractive index of water (1.33) is very close to that of the cornea (which is composed mostly of water). The frog’s ability to focus light decreases, and faraway objects more easily form images on the retina.
