I've been studying for this for nearly a year and have now decided to change one of the pieces, need help on deciding what to though

Bach Partita No. 2 in C minor
Mozart Sonata in D K576
Szymanowski etude No. 3
Piece 4 was going to be Chopin Nocturne in C minor but I just can't get round the last two pages (I have quite small hands), it actually hurts to practise this enough to do it justice, anything about this level that would fit into my programme would be much appreciated.
Thanks in advance
