Which of the Following Environmental Problems Is NOT a Major

Which of the following environmental problems is NOT a major issue in Australia/Oceania?

A) Major mining operations have threatened the environment.
B) Global warming threatens to drown islands of the region as sea levels rise.
C) Wide-scale burning of forests after they have been cleared is creating smoke pollution.
D) Exotic plants and animals are leading to the extinction of indigenous species.
E) Woodlands have been destroyed to produce pastures.