A patient visits the doctor's office with abdominal pain of two days' duration. Medical history is significant for tonsillectomy and hypertension. The patient denies alcohol and drug abuse. The rectal examination confirms heme-negative stool. Impression: Abdominal pain. Which of the following items represents a symptom?
A. Abdominal pain
B. Tonsillectomy
C. Heme-negative stool
D. Hypertension