An environmental issue associated with in south and southeast asia includes the unnatural distribution of sediments, which may lead to flooding . a. slash-and-burn farming b. dam building c. aquaculture d. coal mining

The answer is 
B. Dam Building

The correct answer is B. dam building.
A and D don't really have much to do with flooding. Aquaculture cannot lead to the unnatural distribution of sediments. B is the correct answer because if dams are built incorrectly, they can cause many problems, such as flooding (which they are supposed to prevent), as well as problems with sediments.