Paint + et = painter - someone who paints
kind + ness = kindness - someone who is kind
invent + or = inventor - someone who invents
great + ness = greatness - something to be achieved, by a leader or a country (for example)
I’m pretty certain it’s d because it does not state anywhere that the sound waves are not powerful enough to make the vocal engine useful. hope this helps brainlist would be much appreciated :)
