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'.
Q: Question: In the survey investigations, we work with a representative sample of the population. What does this mean ?:
Options: <1> The sample faithfully reflects the variables that characterize the population and its size is adequate. <2> The conclusions of the study only describe the specific sample and are not generalizable. <3> We obtain incomplete and biased information by the characteristics of the sample. <4> The basic criterion of inclusion in the sample is the accessibility of the participants. <5> The size of the sample should be as close as possible to that of the population.
A:
1