Natural Nutrient enrichment of streams and lakes is

Option b) is correct as eutrophication is the ecosystem response to the addition of artificial or natural substances in the water bodies.

Option a) is incorrect as water pollution is any chemical, physical or biological change in the water bodies that affects the aquatic life.

Option c) is incorrect as Air pollution is the contamination of the atmosphere by harmful and undesirable gases.

Option d) is also incorrect as it relates to the unpleasant and undesirable noise that is unpleasant and harmful.