During a Year, Plants Never Use 100% of the Incoming

During a year, plants never use 100% of the incoming solar radiation for photosynthesis. What is a reasonable explanation for this?

A) Plants cannot photosynthesize as well in warm temperatures as in cold temperatures.
B) Plants do not intercept all incoming light, as some light will strike water, bare soil, or rock.
C) The pigments that drive photosynthesis absorb all of the wavelengths of light that are available; however, some of the light is subsequently reflected.
D) At least 75% of all incoming light is reflected, absorbed, or scattered back by clouds in the atmosphere.