The Parents of a 9-Month-Old Infant Tell the Nurse That

The parents of a 9-month-old infant tell the nurse that they have noticed foods such as peas and corn are not completely digested and can be seen in their infant's stools. On which of the following should the nurse base her explanation of this?

A) Child should not be given fibrous foods until digestive tract matures at age 4 years.
B) Child should not be given any solid foods until this digestive problem is resolved.
C) This is abnormal and requires further investigation.
D) This is normal because of the immaturity of digestive processes at this age.