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. Songs produced by chaffinches reared in isolation are cruder than the songs of wild birds. B. The song of a bird reared in isolation suggests which aspects of chaffinch song may be inborn. C. Comparing the crude songs of chaffinches reared in isolation to the songs of wild chaffinches suggests differences as well as similarities. D. Studying the song aspects of chaffinches reared in isolation, researchers have gained a better understanding of the songs produced by wild birds.