Select the combination of letters that when sequentially placed in the blanks of thegiven series, will logically complete the series.

_ N R M Q _ O J N H _ G K E I _ H B F _

Given: _ N R M Q _ O J N H _ G K E I _ H B F _

Now, we check each options.

Option (a): SKMDC (Not Follow)

S N / R M / Q K / O J / N H / M G / K E / I D / H B / F C

Option (b): SJMFC (Not Follow)​

S N / R M / Q J / O J / N H / M G / K E / I F / H B / F C

Option (c): TJLFA (Not Follow)​

T N / R M / Q J / O J / N H / L G / K E / I F / H B / F A

Option (d): TKLDA (Follow)​

T N /R M / Q K / O J / N H / L G / K E / I D / H B / F A

So, the following pattern is: - 6 and - 5 alternately

Thus, correct option is (d).