Explanation:

- Antique: Refers to objects that are old, typically valued for their age, rarity, or historical significance.

- Option 1: Traditional:

- Meaning: Relating to customs or beliefs passed down over time.

- Explanation: While traditional things can be old, they are not necessarily the opposite of antique.

- Option 2: Prehistoric:

- Meaning: Belonging to the period before recorded history.

- Explanation: Refers to a much older timeframe, not a direct antonym.

- Option 3: Modern

- Meaning: Relating to the present or recent times.

- Explanation: The opposite of something old and antique is something new and contemporary, which is modern.

- Option 4: Conventional:

- Meaning: Based on established norms or standards.

- Explanation: While conventional can imply tradition, it doesn't encapsulate newness like modern does.