What is the length of Pakistan-Afghanistan border?

1. 2,640 km
2. 1,430 km
3. 2,230 km
4. 2,523 km

The Pakistan-Afghanistan border (Durand Line) spans 2,640 km, established in 1893. It traverses rugged terrain, including the Hindu Kush mountains, and remains contentious, with Afghanistan disputing its legitimacy.