D.
It could be constipation, but it is also not uncommon for babies to not poop everyday. Just in case stay away from the BRAT diet (bananas rice applesauce toast). If she is constipated this will make things worse. If you have introduced applesauce, give her apple juice. Dilute it 50% with water and this will help her go. But be careful to much will give her the runs. My doc also told me to give my daughter pears, peaches, prunes, plums or apricots to help increase her fiber and help "loosen" things up. Another thing to do is introduce another cereal. Try oatmeal or barley instead of the rice.