Alongitudinal study of 13,000 adolescents in the united states found that for sexual-minority orientations (including bisexual and homosexual), the largest increase for males between ages 13 and 23 occurred in the category, whereas the largest increase for females occurred in the category.

A longitudinal study of 13,000 adolescents in the United States found that for sexual-minority orientations (including bisexual and homosexual), the largest increase for males between ages 13 and 23 occurred in the completely or mostly homosexual category, whereas the largest increase for females occurred in the heterosexual or bisexual.

Explanation:  

As was seen in the study, for the ages of 13-23, in males and females were not quite similar. When the sexual minority orientation was considered only, it was found that most of the men shifted to a 100% or more than 80% homosexual.

For women on the other hand, they mostly changed over to the bisexual or heterosexual category. Surprisingly, it was found out that there were not many people who fell in the bisexual category, among the men and for female, purely homosexual from ages 13 to 23.

i would say b. research typically uses a variety of sources

answer; soren kieregaard was a 19th century danish philosopher;