Unstructured (not controlled, in-depth) interview is an interview design in which the researcher interviews a few people but gathers very in-depth and detailed information. Interview forms are not used in unstructured interviews; the interviews are conducted in a conversation environment. In life story interview the researcher interviews people who reflect the research problem. The interview includes the entire life course in details. The researcher tries to understand the social fact s/he studies through the life experiences of the participants. Oral history is similar to the life story interview. However, in oral history, not the entire life is subject to the interview. The interview includes only a part, a historical period of the life of the participant. The case study is the examination of a social fact in its own social context, through a variety of data gathering techniques. In case study, only a single critical case is examined rather than a larger sample of the population, and the researcher focuses only on this case rather than more general indicators of the research problem. Thus, the researcher may make longer and more detailed observations. The “case” in the case study may be an event, an institution, a group or a person. For example, the case may be a specific hospital, a specific strike, or a person who had an occupational injury. The analysis of documents like books, newspapers, magazines, reports, records, correspondences, proceedings, diaries, memoirs or letters are called document analysis or documentary analysis. There are a number of analysis methods for analyzing documents, such as content analysis or critical discourse analysis. The correct answer is Choice D.