​The international boundary line which separates North Korea and South Korea is popularly known as: ​

Correct option is A

The correct answer is (A) Military Demarcation Line.

Explanation:
The Military Demarcation Line (MDL) is the boundary that separates North and South Korea, established after the Korean War (1950–1953) and is marked by the Korean Demilitarized Zone (DMZ).

Incorrect Options Explanations:

•  49th parallel: Boundary between the U.S. and Canada.
• 24th parallel: Not related to the boundary between North Korea and South Korea.
• Radcliffe line: Boundary between India and Pakistan, established in 1947.

Information Booster:

• Military Demarcation Line:
  • Formed after the Korean War armistice in 1953.
  • Separates North Korea and South Korea.
  • Overseen by the United Nations Command.