On Pacific islands, a newly arrived gecko species, the house gecko, is displacing the previously established mourning gecko in urban areas, but populations of the two species are more stable in rural areas far from human settlement. The house gecko does not attack the mourning gecko, but in areas where insects congregate it prevents the mourning gecko from feeding on them.
Which of the following contributes most to an explanation of the difference between gecko populations in urban and rural areas?
(A) In urban areas, geckos are valued because they eat so many insects.
(B) Geckos defend territories against other members of the same species.
(C) House geckos that arrive on islands are carried there in boats and planes.
(D) In places where there are lighted buildings, insects tend to gather around the light.
(E) Mourning geckos are all females and reproduce asexually, but house geckos reproduce sexually.
为什么选D? 我觉得是因为lighted builings基本都在城市，而insects聚集，house gecko不让mourning gecko吃，导致mg饿死了。而在rural area没有这种情况，所以城市里hs的数量取代了mg，而stable in rural areas 。
