If FOG is written as ENF in a certain code, how will HEN be written in that code?

1. Compare F→E, O→N, G→F: each letter shifts back by one. 2. Apply the same shift to HEN: H→G, E→D, N→M. 3. Combine the shifted letters: GDM. _Source: RRB Group D CEN-02/2018 PYQ, Q.66._