International organisation's question of identity (3)
I believe the answer is:
who
This clue is a double definition.
'international organisation's' is the first definition.
'question of identity' is the second definition.
(I've seen this before)
(Other definitions for who that I've seen before include "The - - , rock legends" , "medical experts" , "Which people" , "Which person?" , "Universal health body" .)