In "Niacin Deficiency [Pellagra]," What Do the Brackets Represent

Multiple Choice

In "Niacin deficiency [pellagra]," what do the brackets represent?

A) that the coder cannot use this code because it is invalid
B) that the word pellagra is a synonym, alternative word, or explanation
C) that the coder must use a combination code
D) that the coder must look up the code for pellagra