
Passage: In the past hundred years, in the area of Dali Lake, the long-term drought has greatly shrunk the grassy wetlands and turned them into saline-alkali land. Grassy wetlands are places where ducks, geese and other kinds of waterfowl nest and hatch. However, with the continuous shrinkage of wetlands, the average decline rate of the population of red sesame ducks in this area is much lower than that of swans.
Question: Which of the following options, if true, gives the best explanation for the inconsistencies in the above?
A. A.The red sesame duck hatches 8 to 10 eggs per litter, and the swans hatch 2 to 3 eggs per litter, the survival rate is about the same.
B. B.The strengthening of this environmental protection measure has slowed the average decline in the number of red sesame ducks, swans and other species of waterfowl.
C. C.Red sesame ducks and swans are migratory birds, and red sesame ducks are more likely to be hunted and killed in the process of migration.
D. D.Apart from wetlands, red sesame ducks gradually learn to nest and hatch in tree holes and cliff holes, while swans fail to do so.
Answer: