Explanation:

- Observe the first letter of each cluster:

- Z, P, F, V (pattern subtracts 10 each step)

- Next letter should be K, (Z-10 = P, P-10 = F, F-10 = V, V-10 = K).

- Move to the second letter:

- F, Y, R, K (pattern backward in the alphabet, subtracting 7 each time)

- Next letter should be D, (F-7 = Y, Y-7 = R, R-7 = K, K-7 = D).

- The third letter follows:

- O, U, A, E (every third letter forward)

- Next letter will be I, (O+6 = U, U+6 = A, A+6 = E, E+6 = I).

- Lastly, the fourth letter:

- E, A, W, S (pattern subtracts 4 each time)

- Next letter should be O, (E-4 = A, A-4 = W, W-4 = S, S-4 = O).

The sequence should fit KDIO.

- Option 1 (KDIO): Is correct.

- Option 2 (KCIO): Incorrect.

- Option 3 (LDIO): Incorrect.

- Option 4 (LCIO): Incorrect.

.