Answer:
The correct answer is - B. Ocean deoxygenation.
Step-by-step explanation:
Eutrophication is the process in which a water body gets excessively rich in nutrients that leads to the algal growth or plankton growth in this region and covers the complete surface or most of the water body.
Due to this algal and plankton growth, there is a significant decrease in the concentration of the dissolved oxygen in water bodies that result in the incapability of supporting the lives found in it. The primary and main reason for this deoxygenation is eutrophication. Ocean deoxygenation is the reduction of the oxygen concentration of the oceans.