Question #N1332

The invention of the telephone was a major breakthrough in communication technology, and it had a profound impact on society. The telephone allowed people to communicate with each other over long distances, which was previously impossible. It also helped to make the world a smaller place.

Which choice most effectively combines the sentences at the underlined portion?
A. The telephone allowed people to communicate with each other over long distances, that was previously impossible.
B. The telephone allowed people to communicate with each other over long distances; which was previously impossible.
C. The telephone allowed people to communicate with each other over long distances, previously impossible.
D. The telephone allowed people to communicate with each other over long distances, a thing that was previously impossible.