Identify two key factors that have contributed to the increase in life expectancy in many developing nations over the past few decades.

Select two options:

A. Increased public investment in clean water and basic sanitation infrastructure B. A decline in rural-to-urban migration rates across low-income regions C. Greater availability and distribution of antiretroviral therapies and essential medicines D. An expansion of industrial manufacturing with minimal environmental regulation E. A reduction in the funding of national childhood immunization campaigns