Psychologist: In a study, researchers gave 100 volunteers a psychological questionnaire designed to measure their self-esteem. The researchers then asked each volunteer to rate the strength of his or her own social skills. The volunteers with the highest levels of self-esteem consistently rated themselves as having much better social skills than did the volunteers with moderate levels. This suggests that attaining an exceptionally high level of self-esteem greatly improves one's social skills. The psychologist's argument is most vulnerable to criticism on which of the following grounds? ['It relies on evidence from a group of volunteers that is too small to provide any support for any inferences regarding people in general.', 'It fails to adequately address the possibility that many of the volunteers may not have understood what the psychological questionnaire was designed to measure.', 'It overlooks the possibility that people with very high levels of self-esteem may tend to have a less accurate perception of the strength of their own social skills than do people with moderate levels of self-esteem.', "It overlooks the possibility that factors other than level of self-esteem may be of much greater importance in determining the strength of one's social skills."]