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: Intrasubject experimental research designs:
Options: <1> They use independent variables not manipulated directly by the researcher but through the selection of the participants. <2> They are based on the verification of independent groups assigned to the experimental conditions. <3> They combine two independent variables based on the characteristics of the participants. <4> They have lower internal validity than the intersubject designs when they do not use random assignment. <5> They use specific control techniques to control the effects associated with the order of application of the experimental conditions.
Output:
5