单项选择题
To the nearest million, how many more students were enrolled in school—both public and private, prek-12—in 1970 than in 1988
A．3,000,000
B．6,000,000
C．10,000,000
D．44,000,000
E． 51,000,000
B．6,000,000
C．10,000,000
D．44,000,000
E． 51,000,000