Thelen's Dynamic Systems Approach to Understanding Motor Development Is Most

Thelen's dynamic systems approach to understanding motor development is most useful for explaining why

A) Kipsigis infants sit, stand, and walk several months earlier than do North American infants.
B) most infants can stand alone by the time they are 12 months old.
C) most infants can walk quite well by 15 months of age.
D) most infants begin to roll over and crawl at the same age.