This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Special Senses, Subject name: Physiology
Olfactory receptor cells belong to which group of cells? 
Select and explain. 
A. Bipolar neurons, B. Fibroblasts, C. Modified epithelial cells, D. Multipolar neurons
A: Bipolar neurons
Answer: A: Bipolar neurons 
Explanation: The receptor cells for the smell sensation are bipolar nerve cells derived originally from the central nervous system itself. Olfactory system has the smallest range of intensity discrimination.