Piles of aluminum cans floating at sea would be an example of macroscopic pollution. So, the correct option is B.
Pollution may be defined as any substance that negatively impacts the environment or organisms that live within the affected environment.
Macroscopic pollutants are large, visible items in waterways or any bodies of water. The first common pollutant is trash: especially plastic waste like bottles, aluminum cans, industrial plastic contaminations, etc.
Therefore, piles of aluminum cans floating at sea would be an example of macroscopic pollution.
To learn more about Macroscopic pollutants, refer to the link;
https://brainly.com/question/14154063