Programming Languages Quizzes Theory Of Computation

Question:
What can be said about a regular language L over {a} whose minimal finite state automation has two states?

Option A):
L must be { aⁿ | n is even}
Option B):
Either L must be {aⁿ | n is odd}, or L must be {aⁿ | n is even}
Option C):
L must be {aⁿ | > 0}
Option D):
L must be { aⁿ | n is odd}

Correct Answer is Option A):
L must be { aⁿ | n is even}