Sea otters can develop purple teeth if they eat a lot of what sea animal?

Sea otters can develop purple teeth if they eat a lot of what sea animal?

A Jellyfish
B Crab
C Sea urchin

Sea otter teeth and even bones can turn purple if they have a diet rich in purple sea urchins. This effect is called echinochrome staining and a similar orangey condition can occur in humans if they eat too many carrots.

The correct answer is Sea urchin.