Answer:
The word should be in "unison"
Explanation:
this device is called the Oscilloscope.
Aperture is controlled by 'diaphragm' in optics.
The accurate answer is
B.Shut off your engine
The reason is if you get confused this is the number one step you should do and it's the smartest. When you shut down your engine you can try to fix your problem. If you left your engine running you'd be giving your engine more energy and you don't want that
Glad to help :)
