The correct answer is option d, that is, the sunlight reaches the bottom.
A community of organisms that thrives on, in, or close to the seafloor is known as the benthic zone. The species living in the benthic zone are known as benthos. The species dwells at the bottom of the freshwater bodies like rivers and lakes.
The plants, which lives in the higher levels of the benthic zone are known as phytobenthos. However, these plants require sunlight in order to perform the process of photosynthesis. Therefore, these bottom-thriving plants are found in water, which is shallow enough for light to reach towards them. These plants are considered as benthic producers that signifies that they utilize the energy from the Sun to generate tissues of plants, which can be consumed by other species.
