Please help me on this CR's question

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.

I cannot understand why the answer is D?

BTW, Mine is B

不明白

这个题似乎是比较两种  gecko的

D只能比较urban 和  rural的不同

在ＲＵＲＡＬ地区，ＨＯＵＳＥ的阻止ＭＯＵＲＮＩＮＧ的，说明ＨＯＵＳＥ比ＭＯＵＲＩＮＧ厉害

在ＵＲＢＡＮ地区，虫子都聚灯下了，所以ＨＯＵＳＥ和ＭＯＵＲＮＩＮＧ都去灯那里，但是ＨＯＵＳＥ厉害，ＭＯＵＲＮＩＮＧ就少了，因为吃不到虫子了