Evaluating each statement for accuracy:
- Regional analysis was prevalent in the Later Colonial period: This statement is accurate. Historical geography frequently employed regional studies, particularly during the colonial era, to comprehend areas under colonial administration.
- Areal differentiation was the dominant approach in the 1930s: This statement is accurate. The concept of areal differentiation, which examines the unique characteristics of geographical areas, became prominent during this decade.
- The emergence of humanistic, radical, and behavioral schools occurred in the 1980s: This statement is inaccurate. These schools of thought originated earlier, approximately in the 1960s and 1970s.
- Post-Modernism in Geography was prevalent in the 1990s: This statement is accurate. Postmodern viewpoints gained considerable influence in geographical research during the 1990s.
Therefore, the accurate combination of statements comprises only (A), (B), and (D).