In base R1 the expanded fraction F1 becomes 0.373737..., and the expanded fraction F2 becomes 0.737373.... In base R2 fraction F1, when expanded, becomes 0.252525..., while fraction F2 becomes 0.525252.... The sum of R1 and R2, each written in base ten is:(A)24(B)22(C)21(D)20(E)19