I don't think its possible to be F... but lets see...
The possible patterns for this are....
RWAE WREA EARW AWER
RWEA WRAE EAWR AWRE
REAW WERA ERAW AEWR
REWA WEAR ERWA AERW
RAWE WAER EWRA AREW
RAEW WARE EWAR ARWE
There are 24 possible combinations there (yes I just worked them out).
You take the 24 and make it 1/24, but then you have the WARE and the WEAR so that is two combinations out of 24 which simplifies to 1 /12.
Your answer is H.
P.S I think I've overdid this :p (let me know how I did :D)
