The visible portion of the electromagnetic spectrum extends from:

• A. 100-400 nm
• B. 210-370 nm
• C. 380-770 nm
• D. 570-891 nm

Answer: (C)

Light that humans can see covers only a limited slice of the electromagnetic spectrum. The wavelengths our eyes respond to are roughly 380 to 750 nanometers. Shorter wavelengths fall into ultraviolet beyond what we see, while longer wavelengths extend into the near-infrared. Among the options, the range that matches the full visible band is 380-770 nm, because it includes violet through red light without stepping into UV or IR. The first range ends at 400 nm, missing much of the blue-green region; the second is entirely ultraviolet; the last starts at 570 nm and extends into near-infrared, skipping the blue and violet portion. So the 380-770 nm range best represents what’s visible.