Question

# In an electric generator, split rings are used for(A) Converting DC to AC(B) Converting AC to DC(C) Reducing power consumption(D) To split the current

Thus instead of changing the motion of the coil, we change the connections after every half-cycle or every $\pi \,radians$of angle rotated. This can be done electronically now but earlier split rings were used.
Therefore the correct option is $(B)$.