Venice carnival – wide angle prime

I’m going to Venice, Italy in February to shoot all the guys dressed up as photographers (and maybe a few of the other costumes too). I’m going to pair my D700 with primes for low weight and speed and expect to take the 50mm 1.8 AF-D and the 85mm 1.8 AF-D.

I have been to Venice before but only during summer time, so I have no inkling of how many people and how much hustle and bustle there will be. I suspect a wide angle would come in handy but don't know which one to go for.

If you were to bring only one wide angle prime of the f2-f2.8 segment, which one would you bring? I am not interested in shooting architecture on this trip so it is only for crowds etc.

Your input much appreciated [also general tips on the Venice carnival] - if accompanied by persuasive carnival photos even more so

Thanks in advance
Xpanded

PS: I have seen the gorgeous carnival pictures captured with the 14-24 but that is too heavy for me.