A 6-Month-Old Infant Is Brought to the Pediatrician for Recurrent

Multiple Choice

A 6-month-old infant is brought to the pediatrician for recurrent colds.The child is fed formula,and the other family members have not been ill.The primary care provider tells the mother that the child's immune system is not yet competent,but will be about 60% of an adult system around age _____ months.

A) 3
B) 6
C) 9
D) 12