Answer:
Option (C)
Step-by-step explanation:
Glacial retreat can be simply referred to as the condition when the rate of melting of ice is higher than the rate of accumulation of snow, or formation of ice.
This glacial retreat leads to the rising of the sea level, which can be one of the major threat to the ecosystem. This can lead to the submergence of many cities that are mostly located near the coastal areas.
Thus, the correct answer is option (C).