Collect or consolidate?

In this endgame from the Russian Superfinal White here took on e6 with the rook and thus refrained from 37.a3 (diagram) which would have given Black the option of playing 37...Rxc5 38.bxc5 d3. With what result, in your opinion?
A) victory for Black;
B) perpetual check after mutual promotion;
C) victory for White.