Answer: The correct answer is relatively hot objects.
Step-by-step explanation:
Electromagnetic spectrum is a continuum of all the electromagnetic waves. They are arranged according to frequency and wavelength.
All objects emit wave according to their temperature.
The relatively hot objects emit the visible light or ultraviolet radiations having higher frequencies while the relatively cold objects emit wave of lower frequencies such as radio wave. The visible lights in the electromagnetic spectrum is seen by naked eyes.
The wavelengths of the visible light lies between 400 nm to 700 nm.
Therefore, the correct answer is relatively hot objects.