The Fact That Parents in Every Culture Use Infant-Directed Speech

The fact that parents in every culture use infant-directed speech, or motherese, when they speak to infants and toddlers is cited as evidence for the conclusion that:

A) parents understand that children's production vocabulary is larger than their comprehension vocabulary.
B) infants are biologically programmed to encourage their caregivers to use an adult conversational style by responding appropriately only when an adult style is used to communicate.
C) infants and toddlers would learn to talk sooner if parents spoke in a normal adult conversational style.
D) parents are naturally predisposed, or biologically programmed, to encourage language development in their infant children.