Which statement below is consistent with the maturational view of motor development?

a. Preterm infants reach motor milestones later than do full-term infants.

b. Infants who spend the first two years of life lying on their backs walk at later ages than other children.

c. Infants who practice the stepping reflex daily walk earlier than those who do not.

d. Infants who spend time lying on their stomachs each day will crawl earlier