Explanation:

- Flaunt: This means to show something off to draw attention or admiration.

- This is the correct option. Youngsters often wear smartwatches to display them as trendy accessories.

- Recruit: This means to enlist someone for a job or task.

- Not suitable as it doesn’t relate to the context of wearing an accessory.

- Efface: This means to erase or remove something completely.

- Not relevant, as the context is about displaying, not removing.

- Impel: This means to drive or urge someone to do something.

- Not applicable as the context focuses on wearing something as an accessory.

- Replace: This means to take the place of something or substitute it.

- Doesn't fit here because the context is about showcasing, not substituting the item.