The correct option is
A Rubisco
Ribulose-1,5-bisphosphate carboxylase/oxygenase, commonly known by the abbreviation RuBisCO. Rubisco is the most abundant enzyme in the world. It is present in every photosynthetic organism, from the smallest cyanobacteria and plankton to palm trees and giant sequoias. It is abundant because it made organic products that could be used in respiration for nearly every living organism.
So, the correct answer is option A.