The word "presented" in Line 3 of Paragraph 5 can be best replaced by ______.

A．Hispanics are the largest ethnic group in the United States.
B．All Hispanics in the US are thought to be legal immigrants.
C．Though slowing in population growth, African-Americans will still become the second largest minority in the US.
D．The white, non-Hispanic majority in the United States of America will always decrease in numbers twenty years from now.

A．population growth in developing countries
B．why the world' s population is changing
C．how the population is going to change in different parts of the world in the future
D．the sharp contrast in population changes between developing and developed countries