BDA, FHE, ?, NPM

Concept: In a letter-series made of three-letter groups, convert each letter to its alphabet position (A=1, B=2, ..., Z=26). Compare two consecutive known groups position-by-position to find the constant numeric shift between them, then apply that same shift to generate any missing group.

Application:

1. Convert BDA to positions: B=2, D=4, A=1.

2. Convert FHE to positions: F=6, H=8, E=5.

3. Find the shift from BDA to FHE letter by letter: 6-2=4, 8-4=4, 5-1=4 -- every letter advances by exactly 4 positions.

4. Apply the same +4 shift to F, H, E: F+4=J (6+4=10), H+4=L (8+4=12), E+4=I (5+4=9).

5. So the missing group is J, L, I -- written as JLI.

Cross-check: Apply the same +4 shift to J, L, I and confirm it lands on the group already given at the end of the series: J+4=N (10+4=14), L+4=P (12+4=16), I+4=M (9+4=13) -- exactly N, P, M as given. The +4 shift holds consistently across all four groups, confirming JLI as the missing term.