Solid Food Introduction Age for Infants

During a routine well-child visit, the nurse is assessing a 6-month-old infant's growth and development. The nurse notes that the infant is able to sit without support and has begun to babble. It is also important for the nurse to educate the parents about the introduction of solid foods. The nurse explains that solid foods should be introduced around the age of ____ months, with iron-fortified cereals being one of the first options. Additionally, the addition of a new food should occur every few days to monitor for allergies. What is the correct age (in months) to introduce solid foods to this infant?