TOEFL Reading: ETS-TOEFL阅读机经 - SU17FEEG72OP30V7L$

Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information. A. It is more advantageous for birds to choose central locations for their colonies rather than locations near the edges of their territory. B. Compared to nests at the edges of colonies, centrally located nests are preferred for their safety from predators and therefore are more densely packed together. C. Predators generally prefer the densely packed, central portion of nesting colonies, which can make this part of the colony more vulnerable to predators. D. Birds nesting in colonies that are vulnerable to predators tend to prefer more densely packed nests to those less densely packed.