Fact 1: Adoorbell converts electrical energy into sound.

Fact 2: Unwanted sound is noise .

Given the two facts above, answer the question "Which of the following converts electrical energy into noise?" with the following options: 
- a light bulb
 - organ
 - a motor
 - a doorbell
 - a generator
 - vehicles
 - sensory neurons
 - engines


 

    a doorbell     