Which Piece of Evidence Suggests a 'Nurture' Contribution to Left-Handedness

Multiple Choice

Which piece of evidence suggests a 'nurture' contribution to left-handedness

A) The proportion of left-handers is relatively constant across cultures.
B) Ultrasound scans show that 10% of fetuses suck their left thumb.
C) Left-handedness is less prevalent in collectivist than in individualist societies.
D) Left-handedness seems to transmitted by a gene on the X chromosome.