The most extensive climate types over land, dominating 35 percent of earth's land area, are climates.

This fits the description of the tropical climates. This category includes:
a) Tropical Rain Forest climate;
b) Tropical Monsoon climate; and
c) Tropical Savanna climate.

You not be doing this in a quiz. if you actually studied your work you would know the answer. the answer though is that they would use gdp per capita because it measures a smaller portion (person). this could show individual growth per person in the country.