The gross domestic products (GDP) and total populations of four countries A, B, C and D in appropriate units are shown in the accompanying figures.

Countries with the highest and the lowest per capita GDP are, respectively

Correct option is A

Solution:
Since populations of 2 countries A & D is equal, i.e. A = D
But per capita GDP of country A is the highest and D is the lowest
i.e. A > B > C > D
For high GDP per Capita 
- High total GDP 
- Low Population
GDP per capita = Total GDP/Total Population
Therefore, the highest per capita GDP is country A
Now population from highest to the lowest i.e. C > B >A or C.
Due to the highest population of C, per capita GDP is the lowest.
Hence, the countries with the highest and the lowest per capita GDP are A & C.