Explanation:

To solve the sequence, we'll break down the patterns in the letter-clusters:

- First letters (m, k, i): Each letter decreases by 2 (m to k: -2, k to i: -2).

- Second letters (n, p, r): Each letter increases by 2 (n to p: +2, p to r: +2).

- Third letters (l, j, h): Each letter decreases by 2 (l to j: -2, j to h: -2).

Following the pattern:

- First letter after 'i' should be 'g' (i - 2 = g).

- Second letter after 'r' should be 't' (r + 2 = t).

- Third letter after 'h' should be 'f' (h - 2 = f).

Therefore, the sequence is "gtf."

- Option 1: gtf: Follows the correct pattern.

- Option 2: gue

- Option 3: hsg

- Option 4: guf