The atoms of blue paper blue light.
absorb
reflect
transmit

Option C, reflect

Explanation:

The color of any object or thing is depended on the wavelength of light reflected by it.  

Thus a blue color paper appears blue to the viewer as it is reflecting the wavelength of blue light from the spectrum. Like wise a substance appearing white reflects all wavelength of the light spectrum.  

Hence, the color visible to us is due to the reflection of that color light from the spectrum of light falling on it and rest all other light colors are either absorbed or transmitted.  

i'm pretty sure it's spores