The expansion of railroad lines and construction of steel skyscrapers were possible due to-

What explains the increase in life expectancy in botswana? a. the increased availability of jobs and an improved economy b. access to antiretroviral drugs, hiv/aids education, and widespread hiv/aids testing c. a series of military takeovers that stabilized the political system and led to education reform and increased literacy rates d. a recent military coup that led to an improved healthcare system select the best answer from the choices provided.