A nurse is assessing pain in a 6-month-old infant. Which of the following assessment tools should the nurse use?

A. The pain word scale relies on a child verbalizing the intensity of pain using descriptive terms such as "mild," "moderate," or "severe." Infants, including a 6-month-old, are not developmentally capable of verbalizing pain, so this tool is not appropriate for accurate assessment in this age group. B. The PIPP-R (Premature Infant Pain Profile–Revised) is designed for preterm and term neonates, particularly those under 1 month old. It measures physiological indicators like heart rate and oxygen saturation, along with facial expressions. Although it is useful for very young infants, it is less validated for older infants such as a 6-month-old, who may demonstrate more varied behavioral responses to pain. C. The FACES Pain Scale is intended for children aged 3 years and older who can cognitively understand and point to a face that represents their pain level. A 6-month-old cannot comprehend the concept of self-reporting using pictorial representations, making this scale inappropriate. D. The FLACC scale is specifically designed for infants and young children from 2 months to 7 years old who cannot reliably self-report pain. It assesses five behavioral categories: facial expression, leg movement, activity level, cry, and consolability. Each category is scored from 0 to 2, allowing nurses to quantify pain objectively. This tool captures both subtle and obvious behavioral cues, making it highly effective for assessing pain in a 6-month-old infant.