Wayne and Margaret Dennis Found That Traditionally Raised Hopi Infants

Wayne and Margaret Dennis found that traditionally raised Hopi infants who had been strapped to cradle boards:

A) were significantly delayed in all aspects of motor development.
B) learned to walk independently later than infants for whom cradle boards were not used.
C) learned to walk independently earlier than infants for whom cradle boards had not been used.
D) did not differ in age of independent walking from infants for whom cradle boards were not used.