Select the option that represents the letters that, when sequentially placed from left to right in the blanks below, will complete the letter series.
B _ _ CM_ NDC _ BN _ _ M _ _ DCM

Correct option is B

Let's fill in the blanks with the correct letters from option (b) and highlight the filled letters in bold.
Given sequence with blanks:
B _ _ CM_ NDC _ BN _ _ M _ _ DCM
Option (b): NDBMDCBN
Filling in the sequence with option (b):
B N D CM B NDC M BN D C M B N DCM
So, the completed sequence with the filled letters in bold is:
B N D CM / B NDC M /BN D C M/ B N DCM