Parland' s alligator population has been declining in recent years, primarily because of hunting. Alligators prey heavily on a species of freshwater fish that is highly valued as food by Parlanders, who had hoped that the decline in the alligator population would lead to an increase in the numbers of these fish available for human consumption. Yet the population of this fish species has also declined, even though the annual number caught for human consumption has not increased. Which of the following, if true, most helps to explain the decline in the population of the fish species?
A: In several neighboring countries through which Parland's rivers also flow, alligators are at risk of extinction as a result of extensive hunting.
B: Over the last few years, Parland's commercial fishing enterprises have increased the number of fishing boats they use.
C: The decline in the alligator population has meant that fishers can work in some parts of lakes and rivers that were formerly too dangerous.
D: During Parland's dry season, holes dug by alligators remain filled with water long enough to provide a safe place for the eggs of this fish species to hatch.
Choose A, B, C or D as your solution.
D