Could a single person or animal be a cause of point-source pollution

Yes, a single person or an animal can be a cause of point-source pollution.

Explanation:

A point source pollution originates from a definite source or a particular location. This kind of water pollution can be monitored once the source is identified and traced. On the other hand, non-point source pollution is a result of various sources, which are not identified back to a single point.  

In the given case, a single individual or an animal can be a cause of point-source pollution. It is due to the fact that a single animal or an individual is a definite and individual source of pollution.  

i believe it is a.) released into

explanation:

the answer to this question is 3.