The correct answer is 1. The asymmetrical tonic neck reflex (ATNR), a primitive reflex, is present at birth. When the infant turns its head to one side, the upper and lower extremities on the face-side extend while the upper and lower extremities on the skull-side flex. The ATNR typically disappears as an infant's nervous system matures and as they develop more controlled and purposeful movements - by around 6 months of age.