Which of the Following Definitions Is Obscure

Multiple Choice

Which of the following definitions is obscure?

A) Drinking is oral consumption of a fluid substance.
B) A vegan is a vegetarian who does not eat any animal products at all.
C) A pony is a short horse.
D) A cane is a stick, or sticklike device, which a person uses to maintain his/her balance.
E) Trepanning is drilling a hole in the skull down to the dura mater to relieve intracranial pressure.