Which of the Following Is a Broad Measurable Difference Seen

Which of the following is a broad measurable difference seen between male and female infants in the United States?

A) Boys' brains at birth are about 10 percent smaller than girls' brains.
B) Girls are less reactive to stress and more likely to survive infancy.
C) Boys achieve the motor milestones of infancy about 2 months later than do girls.
D) Girls are more vulnerable to illness and fatality since conception than boys.