It's a toss up between b and c. Light which allows you to see things (you can't see light itself, otherwise you wouldn't be able to see through the light !) often known as white light contains all the wavelengths of red orange yellow green blue indigo violet. So on that basis it's B. But, if you pass "white light" through a prism spectrometer, you might also pick up Ultra violet and infrared among other wavelengths depending on the experiment. And that would lean the answer more to C. I'd put 1p on the answer being B ... visible light spectrum ... I think
