Explanation:

- Obsolete means something that is no longer in use or something outdated.

- Option 1: Rigid refers to something that is inflexible or strict. Not related to time relevance.

- Option 2: Remote relates to something being distant or far off. It doesn't oppose the idea of being outdated.

- Option 3: Outdated means something that is old-fashioned or out of date. It's a synonym, not an antonym.

- Option 4: Recent implies something that has occurred or developed not long ago. It directly opposes the concept of being obsolete as it denotes currency and modernity.

- Correct Answer: Recent