The surplus of women among the Kapauku is due to:​

A) ​loss of males through warfare
B) ​unbalanced sex ratio at birth
C) ​trading for women with neighboring groups
D) ​in-migration to the area

The surplus of women among the Kapauku is primarily attributed to the loss of males through warfare, which historically has been a significant factor in altering gender ratios in many societies. Warfare leads to higher mortality rates among men, resulting in a surplus of women.