Fact 1: Telephones are used for communication by two people by transmitting sound.

Fact 2: All sounds are waves produced by the vibrations of material objects.

Given the two facts above, answer the question "Telephones are used for communication by two people by transmitting waves produced by what?" with the following options: 
- The bending of a ray of light
 - movement of tectonic plates
 - the vibrations of soul
 - tectonic plates being pushed together
 - the vibrations of objects
 - the vibrations of the ether
 - movements in the earth's crust
 - the waves of the ocean


 

     the vibrations of objects    