Choose the incorrect pair from the following:

The correct answer is Option (2) → Philatelist : One who collects photographs

A philatelist is a person who collects and studies postage stamps (from the Greek philos, loving). The hobby is called philately. A philatelist has nothing to do with photographs, so this pair is incorrect.
Example: The philatelist showed us a rare stamp from 1854.

Why the Other Options are Incorrect?

Option 1: Numismatist : One who collects coins — Incorrect. Correct use: a correct pair: a numismatist collects and studies coins, notes and medals (from the Greek nomisma, coin).
Example: The numismatist bought an old Mughal coin.

Option 3: Somniloquist : One who talks in sleep — Incorrect. Correct use: a correct pair: a somniloquist talks while asleep (from the Latin somnus, sleep, and loqui, to speak).
Example: My brother is a somniloquist who mutters cricket scores at night.

Option 4: Narcissist : One who loves himself excessively — Incorrect. Correct use: a correct pair: a narcissist is too much in love with himself (after Narcissus, the youth in Greek myth who fell in love with his own reflection).
Example: Only a narcissist would post fifty selfies a day.