Final answer:
Observation is the most passive data collection method among the options given, as it involves the researcher watching subjects without intervention, unlike questionnaires, interviews, or experiments. D. Observation
Step-by-step explanation:
When evaluating which data collection method is the most passive, we must consider the level of interaction between the researcher and the subject. Among the given options, observation comes across as the most passive method. Observational studies require researchers to collect data without interfering with the subjects or the environment. This technique stands in contrast with questionnaires and interviews, where participants are actively engaged in responding to specific questions, and experiments, where researchers manipulate variables and control conditions to observe outcomes.
Observational research can come in various forms like naturalistic observation, where the observer does not intervene with subjects and their natural behaviors, making it a highly passive approach. In fields such as sociology and psychology, observation allows researchers to gather data in a real-world setting, which can lead to rich insights and a deeper understanding of the subjects under study. Nonetheless, passive observation has limitations, such as the inability to infer causality from the data collected or ensure that findings are representative of a larger population due to potentially small sample sizes.