The Symbol AnBn Is Standard Notation for the String That

The symbol AnBn is standard notation for the string that consists of ______.

A) an A,followed by an n,followed by a B,followed by an n
B) an equal number of A's and B's,arranged in a random order
C) n consecutive A's,followed by n consecutive B's
D) a pair of an A and a B,followed another pair of an A and a B