There are no appropriate examples in the list you provided with your question.
Examples of radiation:
... sunshine to tan your skin
... radio energy to bring you the news
... X-ray to check your teeth
... microwave to heat up the meatloaf
... flashlight to see where you're going
... RF energy to get an MRI of your knee
... infrared radiation from the campfire to warm your tootsies
... UHF radio waves to make a call or check Facebook with your smartphone
I would say the answer to your question is A Ferris wheel turning at a constant speed. The reasoning behind this answer is the fact that traveling in a constant direction at a constant speed is not accelerating. The Ferris wheel is the only option that fits this description. The last option would be incorrect due to independent causes such as speed limit changes as well as turns and stops on the highway.
Higher voltage means faster rotation. Changing the voltage polarity changes the direction of the motor.
Potential difference across the entire cd player is 12 V
