Which sentence uses dashes correctly?

A. Uluru is also known as Ayers Rock—it is a large sandstone formation in central Australia.

B. Australia is home to some unusual animals such as kangaroos—wallabies—koalas—kookaburras.

C. Ballaratone is of the centers of the 19th century Australian gold rush and gold is still being mined—today.

D. Sydney draws visitors from all around the world to see its iconic architectural masterpiece—the Sydney Opera House.