Objects around a room — select the meaningful order connecting usage and containment: 1) Key 2) Door 3) Lock 4) Room Choose the order that reflects how these elements relate in practice.

Introduction / Context:
In sequence-of-words questions, items should be arranged to reflect natural dependency or usage. Here, a key acts on a lock installed on a door that grants entry to a room. Understanding containment and action relationships is essential.

Given Data / Assumptions:

• Items: Key, Door, Lock, Room.
• We consider practical everyday usage.

Concept / Approach:
Think in terms of action flow and containment: a key operates a lock; a lock is fitted onto a door; a door provides entry to a room. Ordering should cascade from tool → mechanism → boundary → space.

Step-by-Step Solution:
Step 1: Start with 1 (Key) — the tool used first.Step 2: The key acts on 3 (Lock).Step 3: The lock is mounted on 2 (Door).Step 4: The door opens into 4 (Room), the enclosing space.Final sequence: 1, 3, 2, 4.

Verification / Alternative check:
Reverse-engineer containment: Room contains a Door; Door contains a Lock; Lock is operated by a Key. Inverting containment yields the operational order above.

Why Other Options Are Wrong:

• 4, 2, 1, 3: Begins with the container; does not reflect action flow.
• 1, 2, 3, 4: Puts Door before Lock; the key does not directly act on the door.
• 1, 2, 4, 3: Places Room before Lock; illogical.
• 3, 1, 2, 4: Puts Lock before Key; action begins with the key in hand.

Common Pitfalls:
Confusing structural containment with operational steps. The action starts with the smallest agent (key) and moves outward.

Final Answer:
1, 3, 2, 4