The World's Economies Can Be Divided into Four Main Categories

The world's economies can be divided into four main categories according to their annual per-capita income levels: low-income, lower middle-income, upper middle-income and high-income economies. What category would sub-Saharan Africa fall under?

A) low-income
B) upper middle-income
C) high-income
D) lower middle-income
E) Sub-Saharan Africa falls between lower-middle and upper-middle.