Answer the following question given this paragraph: 

Electric substations have several functions. Many substations distribute electricity from a few high-voltage lines to several lower-voltage lines. They have electric transformers, which use electromagnetic induction to change the voltage of the current. Some transformers increase the voltage; others decrease the voltage. In the Figure below , you can see how both types of transformers are used in an electrical grid.


Q: Electric substations have what devices, which use electromagnetic induction to increase or decrease the voltage of the current?

 Choices:

- transistors

- generators

- tubes

- transformers

A:
transformers
