Fact 1: Adoorbell converts electrical energy into sound.

Fact 2: Speakers convert electrical energy into sound waves.

Given the two facts above, answer the question "What energy does a door doorbell need to be heard through speakers" with the following options: 
- consumers
 - Solar
 - Motion
 - to move people
 - sensory neurons
 - Wind
 - it needs them
 - Electrical


 

        Electrical 