Your patient comes to you with typical signs of pneumonia: high fever, shortness of breath, and persistent cough. Several tests are performed to determine the causative agent of the disease. You observe that you are unable to culture the microbe using standard microbiological media (such as nutrient agar). Furthermore, use of fluorescent probes reveals that the pathogen has a genome composed of single-stranded RNA. Which of the following microorganisms are you most likely observing? Select all that apply.
a) Fungus
b) Bacterium
c) Prion
d) Virus