Explanation:

- Let's break down each letter cluster to see how they relate to each other:

- DFIM: Here, each letter is followed by the next vowel. D to F (two letters apart), I (vowel), M (vowel).

- FHKM: F to H (two letters apart), K (vowel) to M (next consonant).

- MORV: M to O (two letters apart), R (vowel to consonant), V (next consonant).

- QSVZ: Q to S (two letters apart), V (last consonant before vowel), Z (no pattern).

- All clusters except FHKM contain two letters followed by a sequence. FHKM deviates in its arrangement as it doesn't follow the same pattern consistently and sticks more to consonants.

Therefore, the odd one out is:

Option 2: FHKM