Definition: In this task, you are given a multiple-choice question about healthcare. Answer the question based on your information and classify your answers into '1', '2', '3', and '4'.
Input: Question: What is allodynia ?: 
 Options:  <1> Painful sensation triggered by non-painful stimuli. <2> Abnormal sensation, but not painful. <3> Sensation in which the patient has a high threshold of stimulation. <4> Tingling or numbness <5> Painful sensation increased in front of a painful stimulus.
