Four letter-cluster have been given out of which three are alike in some manner, while one is different, Choose the odd one

Four letter-cluster have been given out of which three are alike in some manner, while one is different, Choose the odd one

(a) BHQJ

(b) GMUF

(c) MSBY

(d) RXGT

Sol:

Pattern follows here is +6, +9 Opposite letter.