Answer:
A. Chloroplasts.
Explanation:
Chloroplasts are organelles found in leaves of green plants and they conduct photosynthesis. They contain chlorophyll pigment which captures sunlight and convert it to energy.
Photosynthesis is the process whereby green plants manufacture their food from carbon dioxide and water in the presence of sunlight and they release the oxygen.
So, in the presence of chloroplast, photosynthesis takes place and oxygen is released into the atmosphere.
