The diagram illustrates electricity being sent from a power station to homes many kilometres away. Two transformers are marked X and Y. What are the types of transformers X and Y?
- AX: step-down transformer, Y: step-down transformer
- BX: step-down transformer, Y: step-up transformer
- CX: step-up transformer, Y: step-down transformer
- DX: step-up transformer, Y: step-up transformer