Mary Shook a Rattle for Several Minutes near a Newborn's

Mary shook a rattle for several minutes near a newborn's left ear. The newborn turned her head toward the left. Mary then shook the rattle continuously on the newborn's right, and the infant then turned her head toward the right. About one month later, Mary tried this same procedure again, but the infant did not turn her head in the direction of the rattle. The best explanation for this is

A) at 2 months of age, the infant lost the ability to orient.
B) the infant dishabituated.
C) this is a normal pattern of behaviour; the head turning to the rattle will reappear at 3 or 4 months of age.
D) the infant had the propensity but not the capacity to turn her head.