Explanation:

- Regional Analysis: Focuses on studying specific regions to understand their characteristics and influences. It emerged prominently in geography in the early 20th century.

- Post-modernism: This approach emerged in the late 20th century, challenging traditional narratives and promoting diverse perspectives. It questions absolute truths and encourages multiple realities.

- Spatial Organisation: Examines how people, activities, and processes are distributed in space. It gained momentum during the quantitative revolution in the mid-20th century.

- Areal Differentiation: Concerned with understanding and describing the unique attributes of spaces and places. It has been a fundamental concept since the early 20th century.

Correct Answer: Post-modernism is the most recent approach in Human Geography. This approach began gaining prominence in the late 20th century.