How Has the Fertility Rate in the United States Changed

How has the fertility rate in the United States changed throughout the twentieth century?

A) Between 1920 and 1940, it declined. Between 1940 and 1960, it rose substantially. By 1960, it started to decline again, but since the 1980s it has remained somewhat constant.
B) It has been rising since the 1920s.
C) Between 1920 and 1960, it rose substantially. By 1960, it declined sharply and in the mid-1970s, it remained at the same level.
D) Between 1920 and 1950, and 1960 and 1970, it declined sharply. Since the 1980s, it has remained at the same level.