**Answer:**

The correct answer is option **B** - Australia and Antarctica.

**1. Australia:**
Australia is a continent that lies entirely in the southern hemisphere. It is the smallest of the seven continents and is located between the Indian Ocean and the Pacific Ocean. The continent of Australia is made up of the mainland (also known as the Australian continent) and several smaller islands, such as Tasmania.

**2. Antarctica:**
Antarctica is the southernmost continent on Earth and is also entirely located in the southern hemisphere. It is the fifth-largest continent and is mostly covered by ice. Antarctica is surrounded by the Southern Ocean, and it is home to the South Pole.

**Explanation:**
a) **Australia, South America:** South America is partially located in the southern hemisphere, but it also extends into the northern hemisphere. Therefore, South America does not lie entirely in the southern hemisphere, making option A incorrect.

b) **Australia, Antarctica:** Both Australia and Antarctica lie entirely in the southern hemisphere. Australia is located in the southern part of the Indian Ocean and the Pacific Ocean, while Antarctica is situated at the southernmost part of the Earth. Therefore, this option is correct.

c) **Africa, South America:** Africa is a continent that spans both the northern and southern hemispheres. The equator runs through the middle of Africa, dividing it into the northern and southern hemispheres. South America is partially located in the southern hemisphere but also extends into the northern hemisphere. Therefore, option C is incorrect.

d) **Africa, Antarctica:** Africa is a continent that spans both the northern and southern hemispheres. The equator runs through the middle of Africa, dividing it into the northern and southern hemispheres. Antarctica, on the other hand, is entirely located in the southern hemisphere. Therefore, option D is incorrect.

In conclusion, the only option where both continents lie entirely in the southern hemisphere is option B - Australia and Antarctica.

THE ANSWER IS WRONG
NONE OF THE ANSWER IS CORRECT
THE CORRECT ANSWER :-
SOUTH AMERICA AND ANTARCTICA