Pick up the correct statement from the following: A. The centre line of the approach area coincides with that of the runway B. Approach areas are measured in horizontal surfaces C. Obstruction clearance surface and approach surface are same D. All the above

The correct answer is D. All the above.

The center line of the approach area coincides with that of the runway. This is to ensure that aircraft are aligned with the runway during approach and landing.

Approach areas are measured in horizontal surfaces. This is to ensure that there is sufficient space for aircraft to approach and land safely.

Obstruction clearance surface and approach surface are the same. This is to ensure that there are no obstructions that could interfere with aircraft during approach and landing.

Here is a diagram that shows the different surfaces that are used in airport design:

The approach area is the area that extends from the end of the runway to the touchdown zone. The touchdown zone is the area where the aircraft touches down during landing. The obstacle clearance surface is the surface that is used to ensure that there are no obstructions that could interfere with aircraft during approach and landing. The approach surface is the surface that is used to ensure that there is sufficient space for aircraft to approach and land safely.

I hope this explanation is helpful. Please let me know if you have any other questions.