Task: Question Answering
Input (English): Question: By what name is the disorder known to be characterized by the constant and persistent repetition of words, ideas, or themes, to which the patient continually appeals ?: 
 Options:  <1> Perseveration of thought. <2> Divagatory thinking. <3> Disintegration of thought. <4> Circumstantiality <5> Inhibition of thought.
Output (English): 1