A 9-month-old infant presents with fever and irritability. The nurse notices the infant repeatedly pulls at the right ear, arches the back when touched, and grimaces during diaper changes. Which assessment BEST guides the nurse's interpretation of the infant's pain?

A. Infants cannot verbally communicate pain, so nurses rely on observational cues. Pulling at the ear, arching the back, grimacing, and irritability are valid behavioral indicators of pain and help guide assessment of location and severity. Combining these with physiological signs, such as increased heart rate or changes in respiratory pattern, provides a comprehensive understanding of the infant’s pain. B. Physiological indicators like tachycardia, hypertension, or increased respiratory rate are nonspecific and may reflect stress, fever, or other illness, so relying solely on them is inadequate for pain assessment. C. Infants cannot verbalize pain, but behavioral cues are well-recognized and validated indicators of pain. Assuming pain cannot be assessed without speech is inaccurate. D. Infants do not exhibit pain behaviors to manipulate caregivers. Behaviors such as ear pulling, back arching, and grimacing are genuine indicators of discomfort or pain and should be taken seriously.