Compared with Studies Conducted in the Mid-1990s

Compared with studies conducted in the mid-1990s:

A) the adolescents who choose to engage in sexual intercourse are doing so at an earlier age.
B) fewer adolescents today are engaging in sexual intercourse.
C) regional and ethnic variations make it difficult to generalize about an average age for sexual intercourse for American adolescents.
D) All of the above.