This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Common cold is caused primarily by: 
Select and explain. 
A. Viruses, B. Bacteria, C. Fungi, D. Allergy
A: Viruses
Answer: A: Viruses 
Explanation: Common cold/coryza/Acute Rhinitis is primarily caused by viruses, e.g. Adenovirus, Picorna virus, Rhinovirus, Coxsackie and ECHO viruses. Secondary Invasion by Bacteria Occurs Later.