Correct Option
The correct sequence of continents in decreasing order of their land area is Africa, North America, South America, and Europe.
The approximate land areas of these continents are:
- Africa: 29.8 million sq km
- North America: 21.5 million sq km
- South America: 17.6 million sq km
- Europe: 9.7 million sq km
Based on these figures, the correct decreasing order of land area is Africa > North America > South America > Europe.
Incorrect Options
Option (a) is incorrect because it places North America before Africa. Africa is larger than North America in terms of land area.
Options (c) and (d) are incorrect as they misrepresent the relative sizes of Europe and South America. South America has a significantly larger land area than Europe.