Answer:
B. The change in color is caused by the decrease of the growth of phytoplankton during winter.
Explanation:
When water looks green, it is because there are a lot of microscopic algae called phytoplankton growing near the surface.
Phytoplankton get energy from sunlight, during winter their contribution of photosynthesis is greatly reduced, and a lot of the algae die during the winter, making the water less green.
