There are two stations A and B. Which of the following statements is correct? A. The fore bearing of AB is AB B. The back bearing of AB is BA C. The fore and back bearings of AB differ by 180° D. All the above

The correct answer is D.

The fore bearing of AB is the angle between the north direction and the line AB, measured clockwise from north. The back bearing of AB is the angle between the south direction and the line AB, measured clockwise from south. Therefore, the fore and back bearings of AB differ by 180°.

A. The fore bearing of AB is AB is not correct. The fore bearing of AB is the angle between the north direction and the line AB, measured clockwise from north. Therefore, the fore bearing of AB is not AB.

B. The back bearing of AB is BA is not correct. The back bearing of AB is the angle between the south direction and the line AB, measured clockwise from south. Therefore, the back bearing of AB is not BA.

C. The fore and back bearings of AB differ by

180° is correct. The fore bearing of AB is the angle between the north direction and the line AB, measured clockwise from north. The back bearing of AB is the angle between the south direction and the line AB, measured clockwise from south. Therefore, the fore and back bearings of AB differ by 180°.