While many teens who are sexually active report using contraception at last intercourse, it is difficult to tell

A) from where they are purchasing the contraception.
B) who has taught them to use the contraception.
C) if they switch forms of contraception over time.
D) whether they use contraception consistently and correctly.

D) whether they use contraception consistently and correctly. More teens who consider themselves to be sexually active report using contraception at last intercourse—83% of females and 91% of males used some method. However, it is difficult to tell from these surveys whether sexually active teens always use some form of contraception and whether they correctly use contraceptives; several studies indicate that they do not.