How do I delete Yahoo answer account?

You can't, because NO ONE has a separate YA account account. You have to deactivate your entire Yahoo email account. That can take up to 120 days. If you leg back into that email account, you reactivate it. Deleting your Yahoo ail account will NOT delete your YA content from Verizon/Yahoo's digital databases. Verizon Media OWNS all YA content and it remains accessible forever. You accomplish nothing accept cutting off your access to YA. 

This is how to close your account: https://help.yahoo.com/kb/SLN2044.html