- AMF
- BNG
- CGN
- DNF
Step-by-Step Solution
Two things happen together: the two letters change places, and each then moves forward by 1. C, H swap to H, C and step forward to I, D. Doing the same to F, M gives M, F swapped, then stepped forward to N, G. 'MF' performs the swap but forgets the step, 'GN' performs the step but forgets the swap, and 'NF' steps only the first letter.
Answer: B) NG