This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General physiology, Subject name: Physiology
Weber Fechner Law is 
Select and explain. 
A. Magnitude of stimulus strength perceived is approximately propoionate to the log of the intensity of stimulus strength, B. Magnitude of stimulus strength perceived is directly propoional to the intensity of stimulus strength, C. Threshold of receptor is directly propoional to stimulus strength, D. Threshold of receptor is inversely propoional to stimulus strength
A: Magnitude of stimulus strength perceived is approximately propoionate to the log of the intensity of stimulus strength
Answer: A: Magnitude of stimulus strength perceived is approximately propoionate to the log of the intensity of stimulus strength 
Explanation: The magnitude of the sensation felt is propoional to the log of the intensity of the stimulus (Weber-Fechner law) . It now appears, however, that a power function more accurately describes this relation. In other words, R = KSA where R is the sensation felt, S is the intensity of the stimulus, and, for any specific sensory modality, K and A are constants. P = K lnS/S0 (REF: Ganong's review of medical physiology 23rd Edition page no.153)