The World Bank set an international poverty line at $1.90 a day. According to data from 1990 and 2015 on the number of people below the poverty line, poverty has approximately

a. doubled in Sub Saharan Africa, but stayed constant for the World as a whole.

b. decreased by over 60% for the World, but increased by 20% in South Asia

c. decreased by 95% in East Asia, but increased by almost 50% in Sub-Saharan Africa

d. halved for the world, but stayed constant in Sub Saharan Africa.