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'.

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.
1