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: What is the therapeutic objective of Covert Sensitization ?:
Options: <1> Develop an attraction response to a stimulus that was previously a source of aversion. <2> Increase the tolerance to an aversive stimulus and reduce the emotional activation it produces. <3> Postpone immediate positive reinforcers of undesirable behaviors. <4> Develop an aversion response to a stimulus that was previously a source of attraction. <5> Mentally reinforce successful trials aimed at achieving objective behavior.
4