In a certain code language, the word 'wall' is called 'window', 'window' is called 'door', 'door' is called 'floor', 'floor' is called 'roof' and 'roof' is called 'ventilator'. According to this code, on what will a person stand?

Introduction / Context:
This is a classic verbal reasoning problem involving renaming everyday objects. Instead of changing the objects themselves, the puzzle changes what each object is called. The test is whether you can keep track of the real-world meaning versus the new code name. Here, several familiar items like wall, window, door, floor, roof and ventilator are relabelled, and we are asked to identify on what a person will stand using those new names.

Given Data / Assumptions:

• 'Wall' is called 'window'.
• 'Window' is called 'door'.
• 'Door' is called 'floor'.
• 'Floor' is called 'roof'.
• 'Roof' is called 'ventilator'.
• A person normally stands on the floor in real life.

Concept / Approach:
In such renaming questions, we must always think in two layers. First, identify the real object that satisfies the condition (here, what we truly stand on). Second, convert that real object into its coded name according to the given mapping. It is important not to confuse the code names with the actual physical objects.

Step-by-Step Solution:
Step 1: In the real world, a person stands on the floor of a room or building. Step 2: Now check the code mapping for the word 'floor': the statement says 'floor is called roof'. Step 3: This means that whenever we want to refer to the object floor in the coded language, we must say 'roof'. Step 4: Therefore, in the coded language, the sentence 'A person stands on the floor' would be expressed as 'A person stands on the roof'. Step 5: Hence the correct coded answer to the question is 'Roof'.

Verification / Alternative check:
We can also verify this by mentally reversing the mapping. If someone says 'A person stands on the roof' in this artificial language, using the dictionary we can decode 'roof' back to its real-world meaning 'floor'. That confirms that choosing 'Roof' as the answer correctly represents the place a person stands on.

Why Other Options Are Wrong:
Option A: Window refers to an object that is actually the wall in the code language, not the surface we stand on. Option B: Wall refers to the actual window, which again is not the walking surface. Option C: Floor is the real-world object, but the question asks for the coded word, not the original term. Option E: Ventilator is the new name for roof, which itself was the real roof, not the floor.

Common Pitfalls:
A very common mistake is to answer with the real object instead of its coded name. Some students see 'On what will a person stand?' and immediately mark 'Floor' because they forget to translate into the artificial language. Others get confused by the chain of renaming and accidentally pick 'Wall' or 'Window'. Drawing a small two-column table (real object versus code word) is a reliable way to avoid confusion in such questions.

Final Answer:
According to the given code language, a person will stand on the Roof.