To calculate the GNI per capita for each country, we divide the GNI by the population.
Country A: GNI per capita = $3,900 / 80 = $48.75
Country C: GNI per capita = $10,000 / 1,000 = $10
Country B: GNI per capita = $4,500 / 200 = $22.50
Country D: GNI per capita = $2,000 / 200 = $10
Therefore, Country A has the highest GNI per capita at $48.75.