50.White to move

In the position above it seem an equal position for both side.The question is

a)From your point of view what is the best continuation for white to play?

Thanks again to name and Eugene for participate in solving problem 49 and yes correct eugene with accurate play Black can save the game with a draw. 1....Rxb2 2.Kxb2 Be5 3.f6+ Kf7 4.Rd1 Bxd4+ 5.Rxd4 Nd5 and other continuation 1...Rxb2 2.Kxb2 Be4+ 3.Ka1 (3.Kc1 Nd3+) Nc2+ 4.Ka2/Kb1 Nb4+ a draw by threefold repetition.