Explanation:

- Neon (Option 1):

- Symbol: Ne

- Neon is a noble gas.

- It is colorless and odorless.

- Used in neon lights due to its bright glow.

- Krypton (Option 2):

- Symbol: Kr

- Another noble gas.

- Found in trace amounts in the atmosphere.

- Used in lighting and photography.

- Argon (Option 3):

- Symbol: Ar

- A common noble gas.

- Used in welding and preserving historical documents.

- Oxygen (Option 4):

- Symbol: O

- Not a noble gas.

- Essential for respiration in most living organisms.

- Highly reactive and forms compounds easily.

Option 4 - Oxygen is the correct answer.