Ceiling is the upper interior surface of a room or other similar compartment. Ceiling in a building is at the very top. Ground floor is at the very bottom of the building. Top is generally very far from the bottom in a building.
This justifies what answer for what question? Q & A: 
user
What in the building is very far from the ground floor?
Options:
- basement
- air
- ceiling
- water
- sky
ceiling
assistant