Which of the following organelles are responsible for releasing oxygen into the atmosphere as a byproduct of photosynthesis?

The organelles that are responsible for releasing oxygen into the atmosphere as a byproduct of photosynthesis are chloroplasts. 

During the process of photosynthesis, green plants, algae, and some bacteria use light energy to convert carbon dioxide and water into glucose, a type of sugar that serves as a source of energy and building material for the organism. This conversion takes place in the chloroplasts, which are specialized organelles found in the cells of photosynthetic organisms. As a byproduct of this process, oxygen is released into the atmosphere. The release of oxygen is a result of the splitting of water molecules into hydrogen and oxygen during the light-dependent reactions of photosynthesis. The oxygen produced in this process diffuses out of the chloroplasts and into the atmosphere, where it is available for use by other organisms. This process is vital for life on Earth, as it provides the primary source of oxygen for almost all living organisms.