ELFA, GLHA, ILJA, _____, MLNA

Correct answer: KLLA

Explanation:

Key pattern: the second and fourth letters are constant (L and A). The first and third letters advance by two letters each time.

• First letters: E, G, I, K, M — each step increases by two letters, so the missing first letter is K.

• Third letters: F, H, J, L, N — each step increases by two letters, so the missing third letter is L.

• Second and fourth letters remain L and A respectively, so the missing term is KLLA.