Answer: U

Explanation: Starting on the left, and moving along the line to the right, letters follow the alphabetic sequence, in steps of 1,2,3 and then 4, before repeating the sequence.

A) Q | B) O |

C) M | D) N |

Explanation:

The alphabetical value of the letters in the left hand column follows through the sequence of Prime Numbers, with the letters in the right hand column representing the corresponding reverse alphabetical values. So,

M = Reverse of M = N.

Answer: J

Explanation: Start with the letter J in the top left square, and move clockwise around the other squares. Letters follow the alphabetic sequence, skipping 4 letters at a time. Start with the X in the inner square in the top left, and move clockwise. These inner letters also follow the alphabetic sequence, skipping 5 letters at a time