11. most non-point source pollution consists of a) sewage sludge b) improperly disposed single use items c) oil spilled during extraction, transport, or refinement d) none of the above

A.) sewage sludge

Explanation:

Nonpoint source pollution is pollution resulting from many diffuse sources, for example if several different populations throw their waste in a river they are all nonpoint sources of pollution, as the river pollution comes in small portions from each population but becomes a big problem (it can be factories, farms, etc. And it not only applies to rivers but to other natural environments too.).

In urban development, specially in cities, as the population density grows fast is easier to throw sewage sludge to rivers than to build proper treatment plants, therefore it has become a fairly common source of nonpoint source pollution.