Which is the nurse's best reply when the parents of a 9-month-old infant state that they are worried about their baby's thumb-sucking?

A. Thumb-sucking would be discouraged when the teeth begin to erupt: Eruption of primary teeth does not require immediate cessation of nonnutritive sucking. In infancy, thumb-sucking is a normal self-soothing behavior and does not typically affect dental alignment at this stage. Dental concerns arise only with prolonged habits into later childhood. B. A pacifier would be substituted for the thumb: Substituting a pacifier does not eliminate nonnutritive sucking and may prolong the behavior. Both pacifiers and thumb-sucking serve the same developmental purpose in infancy. Introducing another object is unnecessary when the behavior is developmentally appropriate. C. There is no need to restrain nonnutritive sucking during infancy: Nonnutritive sucking is a normal developmental behavior in infants that supports self-regulation and comfort. At 9 months, it does not pose dental or psychological harm. Intervention is generally not indicated unless the habit persists beyond the preschool years. D. Thumb-sucking would be discouraged by age 12 months: Discouraging thumb-sucking at 12 months is premature and inconsistent with normal developmental expectations. Most children naturally reduce the behavior as they mature. Concern typically arises if the habit continues beyond 3 to 4 years of age.