A 40-year-old self-identified female presents to your clinic with a three-day history of abdominal pain and diarrhea. She reports experiencing vomiting and a low-grade fever. Your initial differential diagnosis is acute viral gastroenteritis. Which signs or symptoms would make you want to consider other differentials?

a. Vomiting
b. Low-grade fever
c. Blood in stool
d. 1-pound weight loss since onset of symptoms