Out of the four alternatives choose the one which can be substituted for the given words/sentences.
One who is honourably discharged from service:
Option B is the right answer.
Emeritus(n): esp. in a college or university, no longer holding the post (but keeping the title of the post) Source: https://dictionary.cambridge.org/dictionary/english/emeritus
retired(adj): stopped working permanently, mostly because of age
relieved(adj): no longer anxious/distressed
emancipated(adj): not limited socially or politically