While Counting the Apical Pulse on a 16-Year-Old Patient,the Nurse

While counting the apical pulse on a 16-year-old patient,the nurse notices an irregular rhythm.His rate speeds up on inspiration and slows on expiration.What would be the nurse's response?

A) Talk with the patient about his intake of caffeine.
B) Perform an electrocardiogram after the examination.
C) No further response is needed because this is normal.
D) Refer the patient to a cardiologist for further testing.