An 8-Year-Old Male Presents with a Red and Sore Throat

An 8-year-old male presents with a red and sore throat. The rapid group A Streptococcus screen is negative, and a sheep blood agar is inoculated. At 24 hours, there are no beta-hemolytic colonies present and moderate growth of normal upper respiratory flora. At 48 hours, the same culture results are present. Which of the following statements does not explain these results?

A) His sore throat is due to Haemophilus influenzae, and it will not grow on blood agar.
B) The culture was taken very early in the infection.
C) The patient received treatment prior to specimen collection.
D) The causative agent is not bacterial.