The Tropic of Capricorn is a circle of latitude around the Earth, it is the southernmost point on the Earth where the Sun can be directly overhead. The question asks which of the listed countries this line of latitude passes through.

Option 1 suggests that only Australia is on the Tropic of Capricorn, but this is incorrect because it isn`t the only country where the Tropic passes.

Option 2 suggests that the Tropic passes through Namibia, Brazil, and Chile, which is partially correct, but still misses Australia.

Option 3 suggests that it passes through Australia, Namibia, and Brazil. This is also only partially correct as it misses Chile.

Option 4 is the correct answer because it lists all the countries which the Tropic of Capricorn passes through, which are Australia, Namibia, Brazil, and Chile.