B. Consensus building
C. Expert intervention
D. Professional perspective
Answer:
A. Participant observation
Explanation:
Participant observation is one kind of information accumulation technique normally utilized in subjective research and ethnography. It is a broadly utilized system in numerous controls, especially social humanities, European ethnology, human science, correspondence thinks about, human geology, and social brain science. Its point is to increase close and personal recognition with a given gathering of people, and their practices through a concentrated contribution with individuals in their social condition, more often than not over an all-inclusive timeframe.