The correct option is C Great Barrier Reef
The only living structure on Earth visible from space, the Great Barrier Reef was born 25 million years ago. The world's largest reef system that stretches for 3,000 kilometres off the Queensland coast has 400 different types of coral and 1,500 species of tropical fish. It is one of the natural wonders in Australia. The Great Wall of China is a man-made structure whereas the Great Dividing Range and the Mount Everest are non-living structures.