Which one is a light gathering structure?

Explanation

The correct answer is the antenna complex. It is specifically designed to gather light by capturing photons through its pigments, such as chlorophyll and carotenoids, and transferring the energy to the reaction center. The reaction center itself is not a light-gathering structure but a site where the energy is utilized to initiate electron transport. The photosystem consists of both the antenna complex and the reaction center, but the antenna complex is the component responsible for light gathering. Therefore, 'None of these' is incorrect because the antenna complex is indeed a light-gathering structure.