Some upset over withdrawal of choices (5)
I believe the answer is:
votes
'choices' is the definition.
(I know this)
'some upset over withdrawal' is the wordplay.
'some' indicates the answer is hidden within the clue (some of the parts of the word are used).
'withdrawal' says the letters should be written backwards.
'setov' is hidden in the letters of 'upset over'.
'setov' reversed gives 'VOTES'.
'of' acts as a link.
(Other definitions for votes that I've seen before include "Casts ballot" , "Elects by ballot" , "Ballots" , "Choices expressed by electorate" , "these should get cast" .)