Charcoal appears black in color because it
a.)emits black-colored light.
b.)has a black colored pigment
c.)absorbs all wavelength of of light that falls on it
d.)reflects all wavelengths of light that fall on it

C. This is the idea of "black body radiation". Charcoal/carbon is a "perfect black body". Absorbs all radiation. There's a whole host of stuff about this in physics, including, I think, Planck's (Nobel Prize winner) black body radiation theory.