Access sequence — arrange items by usage to enter a room 1. Key 2. Door 3. Lock 4. Room

Introduction / Context:
This practical order reflects real-world access: a key operates a lock on a door to enter a room. The logic should respect functional dependencies.

Given Data / Assumptions:

• Key is used first.
• Lock is the mechanism the key operates.
• Door is secured by the lock.
• Room is the destination.

Concept / Approach:
Use cause-and-effect: tool → mechanism → barrier → destination.

Step-by-Step Solution:
1 (Key) → 3 (Lock) → 2 (Door) → 4 (Room).

Verification / Alternative check:
This ordering mirrors typical door hardware use.

Why Other Options Are Wrong:

• They treat door before lock or misplace the final objective (room).

Common Pitfalls:
Assuming the key acts on the door directly; it actuates the lock first.

Final Answer:
1, 3, 2, 4