Geographers might characterize as overpopulated a country where

B) the population numbers are less than one million, but here is concern that the country's natural resources are adequate for only half the number

Explanation:

The geographers tend to characterize the populated regions as overpopulated than those that have a population that is less than one million and they can lead to an increase in the birth rates and decline in the death rates. Overpopulation puts pressure on the resources and thus leads to the drastic rise in the standard of living and growth of the economic output but a decline in percentage share of the resources base of the nation. A country will be said to have overpopulated if the food and other resource are declines fast and nations demographic rises as in the case of Asia, Africa, and South America are said to have a large huge size of population growth.