To Become a "Complete Participant" in His Study Making Gray

To become a "complete participant" in his study Making Gray Gold, Timothy Diamond ________.

A) sought the permission of all of his respondents to observe them
B) went to vocational school to become a certified nursing assistant and took jobs in several nursing homes
C) would visit his mother (who lived in a retirement community) and covertly observe social interactions between staff and residents
D) moved to a gold mining town in Alaska where he spent his evenings in local pubs listening to the workers discuss their difficulties at home and at work