Answer:
B. 4 to 6 months
Step-by-step explanation:
Around the age of 4 to 6 months, babies need extra solid food in addition to the breast milk to help in their growth and also fulfill their nutrients requirement. Also during this age they learned the swallowing of food. But before 4 months it quite risky to give them solid food. So before that breast milk is enough to provide the reuired nutrients.