Final answer:
Primary productivity outside the photic zone can occur in regions like the mesopelagic zone, where there is limited light penetration for photosynthesis and organic matter can drift down from above(option c). This zone still supports some primary productivity thanks to these factors.
Step-by-step explanation:
The question pertains to the occurrence of primary productivity in ocean zones beyond the photic zone, where photosynthesis occurs. It is important to understand that primary productivity can be affected by the availability of light for photosynthesis. In regions like the aphotic zone, photosynthesis is not possible due to the lack of sunlight. This zone starts at depths greater than 200 meters below the ocean surface. Instead, in these deep ocean areas, organisms rely on chemosynthesis to produce energy or consume organic material drifting down from the sunlit waters above.In contrast, photosynthetic organisms, which contribute to primary productivity via photosynthesis, are found in the photic zone, intertidal zone, neritic zone, and oceanic zone. The abyssal zone and the hadal zone are too deep and dark for photosynthesis. The mesopelagic zone and the bathyal zone also fall within the aphotic zone, where photosynthesis is limited due to insufficient light. The question asks specifically about regions outside the photic zone where primary productivity still occurs, which can include the c)mesopelagic zone. Here, some limited primary production can occur near the upper boundaries where faint sunlight might penetrate and also through the influx of organic matter from the photic zone above.