Read the following sentences.

1. Be concise and representative.
2. You may use Gerund and minimize the use of articles (a, an, the).
3. Must be a paragraph long.
4. Share the information beyond the picture shown.
5. The naming should be specific if it focuses on the person or place.
6. Must be outside the picture frame.
7. No need to include the 'above' or 'picture here' description.

Which numbers are used as a technique of writing caption?