The correct option is A Chlorophyll
Chlorophyll is the photo-pigment that absorbs the light energy, which is converted to chemical energy in form of carbohydrates during photosynthesis.
Water is an essential substrate and O2 is a byproduct of the photosynthetic process.
RUBP or Ribulose-1,5-bisphosphate is an organic compound that is involved photosynthesis.