Verified answer

You can only delete open questions.

If the question is still open You can add details by edit / add details under the pencil icon

Once a question has been resolved or is in voting it can only be removed by yahoo if reported and a violation and there isn't a delete option.

The team will remove those that have personal info posted or are violations.

If it does violate the community guidelines or reveal personal contact information, then and only then email them the link to the question.

[email protected] (no e in answrs)

Even closing your account all those resolved stay on the site.

You can only do that if it's Your question and not yet in voting. Once a question has been resolved it becomes the property of Yahoo answers and cannot be deleted. That is part of the rules of the site which you agreed to when you signed up.

if you have already chosen as the best answer, sorry but is no possible