I need help What is the approximate population of North and South America combined

The population of North and South America combined is approximately:
A. 900 million, or about 13 percent of the world's population.
B. 700 million, or about 10 percent of the world's population.
C. 500 million, or about 7 percent of the world's population.
D. 1 billion, or about 15 percent of the world's population.