In the following question, which one set of letters, when sequentially placed at the gaps in the given letter series, shall complete it? JK_MJ_LM_KL_

Introduction / Context:
This is another letter-series completion question in which you must insert a block of letters into several gaps so that the final series follows a clear pattern. The pattern here is particularly elegant: it is based on repeating the four-letter sequence J, K, L, M without any break. The correct option will reconstruct three full cycles of this sequence.

Given Data / Assumptions:
- Incomplete series: JK_MJ_LM_KL_
- There are four blanks in the series.
- Each option gives a 4-letter block to be placed sequentially into these blanks.
- We assume a simple pattern such as repetition of a short letter block is intended, which is typical for this type of question.

Concept / Approach:
The best approach is to try each option and then look for a recognisable letter pattern, especially repeating blocks like ABCD, JKL, or alternating sequences. When you see letters like J, K, L, M already present, suspect that the intended pattern may be a repetition of “JKLM”. The correct inserted letters should therefore restore or complete that repetition without introducing any irregularities.

Step-by-Step Solution:
Step 1: Consider the target pattern: J K L M. Step 2: Try option (c) “LKJM” in the blanks. Step 3: Substitute into the series: JK_MJ_LM_KL_ becomes J K L M J K L M J K L M. Step 4: Now the complete series is: J, K, L, M, J, K, L, M, J, K, L, M. Step 5: This is exactly three consecutive repetitions of the block “JKLM” with no gaps or disruptions. Step 6: Since the series is perfectly regular, option (c) is a strong candidate for the correct answer.

Verification / Alternative check:
Check other options briefly:
- Option (a) “JKLL” gives J K J M J J L M L L with irregular sequences and duplicated letters where the pattern should be smooth.
- Option (b) “LKKM” generates a mixed pattern that does not fit a clean repeating block.
- Option (d) “KJLM” also disrupts the simple “JKLM” repetition.
Only option (c) produces a complete, repeated “JKLM” sequence across all 12 positions.

Why Other Options Are Wrong:
- “JKLL”: breaks the order and introduces LL together, which does not match the alphabetical progression J, K, L, M.
- “LKKM”: introduces repeated Ks and distorts the underlying order, so you no longer see neat cycles of any simple block.
- “KJLM”: shuffles the letters in a way that prevents a regular pattern from emerging.

Common Pitfalls:
Some candidates focus too much on local pairs, such as trying to match only “JK” or “LM”, and miss the larger repeating structure. Another error is to accept a partially ordered fragment and ignore irregularities later. For letter-series questions, always look at the entire resulting sequence after substitution and check whether a simple, repeating rule explains all positions.

Final Answer:
The set of letters that correctly completes the series is “LKJM”, giving three full repetitions of the sequence J, K, L, M.