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.