What is the evidence that the soothing function of sucking need not be learned through experience?

A. Babies mimic the sucking motion when at rest or during sleep.
B. As a baby outgrows colic, their rooting reflex also strengthens.
C. Babies who cry incessantly or become easily agitated typically show a weak rooting reflex at birth.
D. Sucking on a pacifier decreases crying and agitated movement in hungry neonates.

Answer: D