It was established in option b.1911
The correct answer is B. Human Development Index.
The Human Development Index (HDI) takes into consideration several different factors in order to categorize nations as to levels of development. Some of the factors they use are:
A) A country's Gross National Income (GNI)
B) Life expectancy
C) Education of citizens (i.e. college degree, years of schooling for average citizen).
Constantinople briefly served as the capital but was quickly conquered by the Persians.
