Select the set of letters that when sequentially placed in the blanks of the given letter series will complete the series.

_m_ln_mlmnk_k_nl

k, n, k, l, m

By observing all options we find that , only option 2 form a repeated series .

The pattern followed is,

The group of letters ‘kmnl, nkml, mnkl’ are repeated simultaneously.

_m_ln_mlmnk_k_nl

k, n, k, l, m  :-  kmnlnkmlmnklkmnl

Ans = k, n, k, l, m