Which of the following separates white light into different colors?

b. refraction.

Details on the link below -

http://en.wikipedia.org/wiki/Visible_spectrum

That is physics, it is B refraction. Scattering merely passes the light in other directions, transmission does not refer to light waves, absorption does what it says absorb the colors (some are reflected which is what gives color to the world around us, plants absorb a large spectrum of light but green which they then turn to energy via photosynthesis)