I'd try A) first. The cage length only affects capacity, not maximum sprocket size, so the small cage should work with a 32.
Option B) shouldn't be necessary.
Option C) is the fall-back position if the short cage derailleur doesn't have the capacity for 12-32 + 50-34 (36 tooth capacity). The 2014 Campagnolo catalog doesn't show a medium cage Chorus derailleur, but there are long cage Athena derailleurs (in black) that will work with the pre-'15 Chorus derailleurs.
There is also option C2), which is to get a '15+ medium cage Chorus derailleur and '15+ right shifter. You might also be able to get
'15+ lever/body assembly and rebuild your current right lever.
Option D) is obviously possible, but very expensive.