Answer :

To determine the percentage of teens who have had at least 1 drink by age 15, let's analyze the data available from various studies and research.

1. Review Research Findings:
- Studies such as the Monitoring the Future survey by the National Institute on Drug Abuse (NIDA) and other similar surveys provide insights into teenage drinking habits.
- According to these studies, there is a significant percentage of teens who report having had at least one drink by the age of 15.

2. Evaluate the Options:
- Over 90%: This option suggests an extremely high percentage and might be an overestimation considering general trends in teenage drinking.
- About 30%: This suggests a moderate percentage, which seems lower than expected based on research findings.
- About 3%: This is a very low percentage, which is highly unlikely given the context.
- About 75%: This suggests a significant majority of teens, aligning with findings from reliable sources like the Monitoring the Future survey.

3. Choosing the Correct Answer:
- Given the data from research which indicates a notable percentage of teens having consumed at least one drink by age 15, the most accurate answer is:
- About 75%

Therefore, by age 15, about 75% of teens have had at least 1 drink.