According to the Constitution of India, the term ‘district judge’ shall not include

The Constitution’s interpretative provision for the chapter on subordinate courts (Article 236 as reproduced in standard texts) gives an inclusive list of who constitutes a “district judge”, explicitly naming city civil court judges, additional/joint/assistant district judges, the chief judge of a small causes court, chief presidency magistrate (and additional chief presidency magistrate), sessions judge and their additional/assistant counterparts [1]. That authoritative list does not mention members of tribunals. Therefore, among the given options only “tribunal judge” is not included within the constitutional definition of “district judge”, making option 3 the correct choice [1].

Sources

1. [1] Laxmikanth, M. Indian Polity. 7th ed., McGraw Hill. > Chapter 35: Subordinate Courts > CONSTITUTIONAL PROVISIONS > p. 363