What are two main sources of pollution impacting North Carolina's surface waters?

The correct answer highlights agricultural runoff and industrial discharge as the two main sources of pollution impacting North Carolina's surface waters due to their significant contributions to water quality degradation in the region.

Agricultural runoff often contains fertilizers, pesticides, and herbicides that can lead to nutrient enrichment in water bodies, commonly referred to as eutrophication. This process can result in harmful algal blooms, which deplete oxygen in the water and harm aquatic life. Specifically, in North Carolina, agricultural activities are quite prevalent, which makes runoff from farms a critical concern for water quality.

Industrial discharge involves the release of pollutants from factories and manufacturing plants, including heavy metals, chemicals, and other hazardous substances. This type of pollution can severely impact aquatic ecosystems and human health, especially when such discharges are not adequately treated before reaching surface waters.

While other options like sewage and stormwater runoff do contribute to water pollution, and household waste and plastic debris are significant issues, the combination of agricultural runoff and industrial discharge specifically reflects the predominant sources affecting North Carolina's waterways based on state assessments and research.