Final answer:
The most suitable method for a researcher who wants to know what people actually do is behavioral observations, which allows for direct documentation of subjects' actions in their environment.
Step-by-step explanation:
If a researcher wants to know what people really do and not just what they think they do, the advisable method would be d. Behavioral observations. This method is more suitable for capturing actual behaviors since it involves watching subjects in their natural environment and documenting their actions without the influence of self-report bias. However, in some cases, such as studying prisons or clandestine organizations like the Ku Klux Klan, direct observation may be impossible or ethically questionable. In those instances, researchers need to carefully choose alternative methods that are appropriate for their specific research questions, and that ensure the safety and anonymity of the subjects.
Behavioral observations reduce the chances of self-report inaccuracies but also come with the risk of observer bias. Therefore, it is crucial for researchers to establish clear criteria for what behaviors are recorded and to have several observers to enhance inter-rater reliability. On the other hand, surveys, which rely on self-reported information, can gather vast quantities of data quickly but are limited by the honesty and self-awareness of respondents.