Person who chooses answers inferior to A, B, C, followed by drink (7)
I believe the answer is:
decider
'person who chooses' is the definition.
'c followed by drink' is the wordplay.
'c' becomes 'de' (I can't explain this - if you can you should give a lot more credence to this answer).
'followed by' says to put letters next to each other.
'drink' becomes 'cider' (cider is a kind of drink).
'de'+'cider'='DECIDER'
'answers inferior to a b' is the link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
(Other definitions for decider that I've seen before include "The game that determines the series winner" , ""Golden goal", for example" , "Game settling a contest" , "It settles the matter" , "Replay perhaps" .)