Answer:
The Case Study.
Explanation:
The case study is demonstrated as the research method or strategy that involves a proximate and in-depth interrogation of a person, group, process or event in its real-life surroundings.
As per the question, the 'case studies' possess the highest risk of gathering evidence that could be divergent or peculiar such a research deeply evaluates and analyzes the subject or person in its real-life surroundings and gathering evidence is quite difficult as it mostly includes finding archival records or artifacts, personal observations, etc. that may present a false or non-justifiable information that could influence the efficacy of the claim. Thus, 'case study' is the answer.
