Observational Research Has Found That Blind Infants Tend to Show

Observational research has found that blind infants tend to show the same facial expressions as do sighted infants, but as blind infants grow older, their expressions become less animated. This indicates that facial expressions

A) are innate.
B) are learned.
C) may be innate but are maintained by operant shaping.
D) are the result of imitation.