Between 1970 and 2010, the Poverty Rate in East Asia

Between 1970 and 2010, the poverty rate in East Asia declined dramatically from about 60 percent to less than 1 percent, while the poverty rate in sub-Saharan Africa decreased from 40 percent to only 24 percent.The main reason for this is that

A) the population growth rate decreased in East Asia and increased in sub-Saharan Africa.
B) Governments in East Asia increased transfer payments to poor families over this period of time. The governments of sub-Saharan Africa had practically no transfer payment programs from 1970 to 2010.
C) The countries of East Asia have progressive income tax systems. The countries of sub-Saharan Africa all have regressive income tax systems.
D) East Asia experienced higher economic growth than sub-Saharan Africa.