Final answer:
Option A. The true statement regarding adolescent sexual behavior timing in the U.S. is that oral sex is common among American adolescents, not the other options provided about ethnic timing differences or the prevalence of sexual intercourse before the age of 10.
Step-by-step explanation:
Of the statements provided regarding the timing of adolescent sexual behavior in the United States, the true statement is that oral sex is a common occurrence among American adolescents. Statistical data show that a significant number of U.S. teens have engaged in oral sex by the age of 18. In terms of ethnic differences, it is generally incorrect to state that African Americans engage in sexual behaviors later than other ethnic groups or that Asian Americans are likely to engage in sexual behaviors earlier than other ethnic groups.
It's important to note that societal sexual attitudes vary from one culture to another and are influenced by many factors such as the family, education system, peers, media, and religion. Countries with comprehensive sex education programs, such as Germany and Sweden, have different outcomes regarding teenage sexuality and behaviors, including lower rates of teenage pregnancy, compared to countries like the United States, which do not mandate sex education in all public school curricula.