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: Medicine
Uhthoff's symptom is seen in: 
Select and explain. 
A. Multiple sclerosis, B. Poliomyelitis, C. Guillain-Barre syndrome, D. Myasthenia gravis
A: Multiple sclerosis
Answer: A: Multiple sclerosis 
Explanation: Heat sensitivity refers to neurologic symptoms produced by an elevation of the body's core temperature. Uhthoff's symptom is the unilateral visual blurring that may occur during a hot shower or with physical exercise. It is also common in Multiple sclerosis. Such heat-related symptoms probably result from transient conduction block. Ref: Harrisons principles of internal medicine, 18th edition, Page: 3398.