A large aquarium has portholes of thin transparent plastic with a radius of curvature of 1.85 mm and their convex sides facing into the water. A shark hovers in front of a porthole, sizing up the dinner prospects outside the tank.
How far from the plastic does the shark's tooth appear to be to observers outside the tank if one of the shark's teeth is exactly 47.0 cm from the plastic? (You can ignore refraction due to the plastic.)
A: 47.0 cm
B: Less than 47.0 cm
C: More than 47.0 cm
D: Cannot be determined
