The following table shows the symptoms in four patients. Each patient suffers from a different disease.
Patient Disease Cause Symptom
A Tuberculosis Bacteria Chest pain, coughing
B Polio Virus Paralysis
C Stomach cancer Environmental Stomach pain, vomiting, nausea
D Food poisoning Bacteria Vomiting, loose stools
Which patient's digestive system is affected by an infectious agent? (5 points)
A
B
C
D