What does the basic function of a transformer allow it to change?

A is the proper answer to this. The main function of the transformer is to change the level of voltage. Take note that transformers can be used both ways. There are times when they are used to increase the voltage. Sometimes, they are used to lower the voltage. This electrical device is considered to be very important.

The transformer has the tendency to burst when it has become fully loaded for a long time. If this will be done often, the transformer will not last for a long time and would need to be replaced. Proper usage of electricity is important so that this situation can be avoided.