Eskimos Wear a Great Deal of Clothing and Have Limited

Eskimos wear a great deal of clothing and have limited exposure to ultraviolet light, but do not suffer from vitamin D deficiency. A possible explanation is

A) they do not need vitamin D.
B) their exposure to ultraviolet light in the summer will last for a year.
C) they get enough vitamin D in their diet of fish and marine mammals.
D) they do not require sunlight for vitamin D formation.
E) their bodies produce vitamin D another way.