The best form for URL structure

From an SEO perspective, it is generally best to use a clear and concise URL structure that accurately reflects the content of your pages. This can help search engines understand the content of your pages and improve the way they rank in search results.

Here are some tips for creating an effective URL structure:

1. Keep it short and sweet: Use short, descriptive URLs that are easy for users to remember and understand.
2. Use keyword-rich URLs: Include relevant keywords in your URLs, as this can help your pages rank for those terms.
3. Use hyphens to separate words: Use hyphens (-) to separate words in your URLs. This helps search engines understand the individual words in your URL.
4. Avoid using special characters: Special characters like underscores (_) can be difficult for search engines to interpret, so it is generally best to avoid them in your URLs.
5. Use a logical hierarchy: If your website has multiple levels of content, use a logical hierarchy in your URLs to help users and search engines understand the relationships between your pages.

By following these tips, you can create a URL structure that is both user-friendly and SEO-friendly.

In your case the first option may be the best. If you have lots of categories, then maybe you can leave the category name in the url as well.