Final answer:
The percentage of adolescent boys who have at least one same-sex encounter can vary based on studies, and the question doesn't provide enough context to give a direct answer. It is important to reference specific and recent research to obtain accurate statistics.
Step-by-step explanation:
The question pertaining to the percentage of adolescent boys who have at least one same-sex encounter does not have a definitive answer as studies and surveys on this topic may yield different results, and it may also vary by region and over time. Additionally, this data is sensitive and may not always be accurately reported due to various social factors.
To give a direct answer, one would need to refer to a specific study or surveys that have been conducted on this topic. However, in the absence of direct reference to such a study in the question, it is not possible to provide an accurate answer from the options provided.