A 9-year-old girl comes in for a new patient physical with her caregiver. She looks quite small for her age, and her height is a little below the third percentile. Her caregiver has brought in her medical records, and her height and weight have been consistently tracking at the third percentile since around the age of three, but they were both at the 10th percentile when she was born. Her head circumference has stayed around the 25% throughout. Her former provider noted a "constitutional growth delay" based on wrist films that showed a bone age which "corresponds to her height age" per the radiologist's read. How does one determine height age? A. Height age is the age where the child's parents can expect them to be at their maximum height. B. Height age is the age at which the child would be if their height were at the 50th percentile. C. Height age is the age at which the child should be, if their weight were at the 25th percentile. D. Height age is the age where they are achieving normal gains in height, at their present level of height gain