Sunlight is available for photosynthesis primarily in the Epipelagic Zone. This is the surface layer of the ocean that receives enough sunlight to support photosynthetic organisms like phytoplankton.
The other zones listed—Mesopelagic Zone, Bathypelagic Zone, Abyssalpelagic Zone, and Hadal Zone—are deeper layers of the ocean where sunlight does not penetrate effectively, and thus photosynthesis does not occur.
So, the correct option is:
- Epipelagic Zone.