Must I request ripe bananas? (12)
I believe the answer is:
prerequisite
'must' is the definition.
(thesaurus)
'i request ripe bananas?' is the wordplay.
'bananas?' indicates anagramming the letters (informal term for mad).
'i'+'request'+'ripe'='irequestripe'
'irequestripe' is an anagram of 'PREREQUISITE'.
(Other definitions for prerequisite that I've seen before include "Early qualification" , "Needed as a prior condition" , "Something required as a prior condition" .)