A 6-month old has been hospitalized for the treatment of acute diarrhea. Discharge diet includes the use of Isomil instead of Similac formula until the next clinic appointment. Which of the following statements explains the change in infant formula?

D Infants commonly have a lactose intolerance after a diarrheal illness. C Isomil is an excellent oral rehydration formula. A Isomil is less expensive than Similac. B The infant has developed a permanent lactose intolerance.