SAT English Practice Question

The author of the text wants to emphasize the importance of the scientist’s discovery. Which of the following choices best helps to accomplish that goal by adding a modifier to the sentence? The scientist’s discovery—which was made by studying fossils—proved critical to deciphering the human genetic code.

1. A.The scientist’s discovery, which was made by studying fossils, proved critical to deciphering the human genetic code.
2. B.The scientist’s discovery, which was made by studying fossils, proved critical to deciphering the human genetic code.
3. C.The scientist’s discovery, proved critical to deciphering the human genetic code, was made by studying fossils.
4. D.The scientist’s discovery, which was made by studying fossils, proved critical to deciphering the human genetic code.