A mother brings her 4-year-old daughter to your office because of fever and decreased eating and drinking. When you ask the little girl what is wrong, she says her mouth and throat hurt. On examination her temperature is 101 degrees. Her ears and nose examinations are unremarkable. Her mouth has ulcerations on the buccal mucosa and the tongue. She also has cervical lymphadenopathy. Her cardiac and pulmonary examinations are normal. She is up to date on her childhood vaccinations. What mouth abnormality does she most likely have?

a. Strep throat
b. Herpetic stomatitis
c. Oral candidiasis (thrush)
d. Diphtheria