The nurse is assessing a school aged child with ADHD. The child is prescribed dexamethylphenidate 10mg before breakfast and lunch. Which of the following findings is of MOST concern to the nurse?

A. Sleeping 8 to 10 hours a night is within the normal range for a school-aged child. B. A resting heart rate of 90 beats per minute is within the normal range for a child. C. A blood pressure reading of 140/90 is concerning as it indicates hypertension, which can be a side effect of stimulant medications like dexamethylphenidate. D. A weight gain of 2 kgs is not immediately concerning in a growing child, though weight should be monitored.