Answer: the right answer is B natural
Explanation: enharmonic is when two notes with different names (in this case Cb and B natural) have almost the same sound. In the scale, B and C are separated only by a semitone. Therefore, if we play a Cb, we will be playing B natural since there is no B#. The same thing will happen with E and F because they are separated by a semitone. So, if you play Fb, you will be playing E.