You are absolutely right but when I enter my password after expiring of lockout time Yahoo asks me to answer the security question which slipped from my mind so what can I do now?
Yahoo implemented different recovery methods such as alternative e-mail, SMS and others. If you don't remember the answer to your questions, I am afraid that the account is not recoverable and Yahoo Support in no way will grant access.
In case you remember any details, you can go through the answer I stated here.
