What are the correct group names of the World Bank's country classification by income?
A) Lowest income, lower income, middle income, high income
B) Lowest income, lower-middle income, upper-high income, highest income
C) Low income, lower-middle income, upper-middle income, high income
D) Low income, middle income, upper-middle income, high income
E) Lowest income, lower-middle income, upper-middle income, high income