The Authors Mentioned the Interesting Correlation Between Natural Red Hair

Multiple Choice

The authors mentioned the interesting correlation between natural red hair and lower pain thresholds compared to persons with other natural hair colours.This is most likely to be due to the fact that

A) natural pain thresholds cause people to be born with different natural colours of hair.
B) genetic factors that impact pain threshold are also somehow related to hair colour.
C) natural hair colour causes people to have an increased or decreased pain threshold.
D) persons with red hair demonstrate a specific sensitivity to pain in their free nerve endings.