Detailed Instructions: 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'.
Problem:Question: What does the intersessional sampling used in observation techniques refer to:
Options: <1> To the registration of relevant information between sessions. <2> To the periodicity, number and criteria of start-end of the sessions. <3> To the successive rounds of observation of the subjects to observe. <4> To the temporary selection and its interval or partial modality. <5> To the record of focal events that occur between sessions.
Solution:
2