A. Canberra is the capital of Australia
B. 78% of people living in Sydney were born overseas
C. The climate of Sydney is temperate, having warm , sometimes hot summers and mildly cool winters.
D. Sydney is a global cosmopolitan city that boasts an enviable quality of life, and was ranked 10th out of 233 cities in the 2014 Mercer Quality of Living Survey.
So, the correct answer is D)