Multispectral refers to:

A. UV, IR, and visible light
B. the many colors in visible light
C. UV, IR, and x-rays

Thanks!

2 answers

Well, here is an example in which I suspect your text defined. Check that. In general, A or C could be defined, and even B. The original Landsat mapped in Multi-spectral, it used ten wavelengths in Answer A. http://www.classzone.com/books/earth_science/terc/content/investigations/esu101/esu101page07.cfm is an example of near IR and visible.
So which does your text use? Check it. I have never understood instructors that define a general term to mean something very specific. In the real world, Multi-spectral could mean just about anything (Even your TV, RGB is multispectral).
Our text does not even refer to multispectral.