Since 1996, What Has the Trend Been for the Rate

Since 1996, what has the trend been for the rate of births by cesarean section (C-section) in the United States?

A) It has decreased dramatically as more mothers turn to alternative medical options.
B) It has increased dramatically, probably more as a result of cultural conceptions of childbirth than medical necessity.
C) It has increased dramatically, as the medical necessity for C-sections is proven by studies of other cultures.
D) It has fluctuated widely as trends in childbirth have come in and out of cultural acceptance.