Critical Reasoning

Male bowerbirds construct elaborately decorated nests, or bowers. Basing their judgment on the fact that
different local populations of bowerbirds of the same species build bowers that exhibit different building and
decorative styles, researchers have concluded that the bowerbirds' building styles are a culturally acquired,
rather than a genetically transmitted, trait.
Which of the following, if true, would most strengthen the conclusion drawn by the researchers?
(A) There are more common characteristics than there are differences among the bower-building styles of the
local bowerbird population that has been studied most extensively.
(B) Young male bowerbirds are inept at bower-building and apparently spend years watching their elders
before becoming accomplished in the local bower style.
(C) The bowers of one species of bowerbird lack the towers and ornamentation characteristic of the bowers
of most other species of bowerbird.
(D) Bowerbirds are found only in New Guinea and Australia, where local populations of the birds apparently
seldom have contact with one another.
(E) It is well known that the song dialects of some songbirds are learned rather than transmitted genetically.

Could an Expert please explain how to emliminate A and D ,in particular