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: Physiology
The sensory receptors serving the stretch reflex are classified as: 
Select and explain. 
A. Proprioceptors, B. Nociceptors, C. Exteroceptors, D. Chem receptors
A: Proprioceptors
Answer: A: Proprioceptors 
Explanation: None