The correct option is A Generation of ATP and NADPH2
Assimilatory power is the power of plants in the form of ATP and NADPH2 to obtain food in the form of carbohydrates from the reduction of CO2 during photosynthesis.
During the phase of photosynthesis that requires the invlovement of sunlight, also called as the light reaction, the assimilatory powers ATP and NADPH2 are generated along with the evolution of oxygen after the photolysis of water has occured. These assimilatory powers are utilized during the dark reaction phase of photosynthesis (also known as Blackman's reactions) in order to fix carbon dioxide by forming sugars.