In the Late Twentieth and Early Twenty-First Centuries, a New

In the late twentieth and early twenty-first centuries, a new threat to the world economy emerged in the form of

A) a new superpower race between China and the United States.
B) falling fertility rates, resulting in an increasingly elderly population.
C) deadly new contagious diseases, particularly the Ebola virus and severe acute respiratory syndrome (SARS) .
D) widespread famine in Africa and South America.