Which sentence uses a proper adjective? A. Kangaroos live in the Australian outback. B. Green and gold are Australia's official colors. C. Australia is both a country and a continent. D. The land mass of Australia is almost twice the size of Europe.

A proper adjective is like a proper noun, because it is capitalized. For example China is a proper noun, but Chinese is a proper adjective. Therefore letter A is the right answer because it use a proper adjective, which is Australian. Don't get this confused with B because they capitalized green, first of all you have to capitalize green because your starting a sentence and notice that gold is a n adjective but is is not capitalized.