Which of the Following Statements Correctly Summarizes the Contribution of Thelen's

Which of the following statements correctly summarizes the contribution of Thelen's research to the understanding of infant motor development?

A) Newborn stepping movement provides opportunities for early practice before higher order brain centers take over and voluntary walking appears.
B) Early experiences have significant effects on the timing of infant motor skill development.
C) Factors such as weight and muscle mass can impact the type of behaviors that infants display.
D) Motor skills such as standing and walking are predominately controlled by lower centers of the brain.
E) Cultural factors such as encouragement of early standing and walking can accelerate the timing of typical motor milestones.