Concept:
Key sociological and anthropological community studies that utilize ethnographic, observational, and power-structure analysis.
Step 1:
Robert and Helen Lynd conducted a seminal community study of Muncie, Indiana, published as "Middletown: A Study in Contemporary American Culture" (III).
Step 2:
W. Lloyd Warner conducted his famous study of Newburyport, Massachusetts, known as the "Yankee City" (IV) series, focusing on social stratification.
Step 3:
Whyte is known for his classic participant observation study of an Italian-American neighborhood in Boston, titled "Street Corner Society" (II).
Step 4:
Robert Dahl, a political scientist, studied the structure of power in his famous research on the community of "New Haven" (I).
Step 5:
Matching these authors to their works (A-III, B-IV, C-II, D-I) aligns correctly with option (2).
$$\boxed{\text{(2) A-III, B-IV, C-II, D-I}}$$