Four letter-clusters have been given, out of which three are alike some manner and one is different. Select the odd one.

FILO EHKN ADGJ CFIM

CFIM

FILO = F → (+3) → I → (+3) → L → (+3) →O EHKN =F → (+3) → H → (+3) → K → (+3) →N ADGJ = A → (+3) → D → (+3) → G → (+3) →J CFIM = C → (+3) → F → (+3) → I → (+4) →M ( THIS IS ODD)