I cannot update the Apple Developer Program license agreement because I need to bind my mobile phone number before the update, and binding the mobile phone number requires Apple ID account security. Because I forgot the answer to the question. How to do?

I have the same problem, and the https://iforgot.apple.com/password/verify/appleid website still needs to answer one of the three question to reset the Security Question. But I fogot All The Answer of these three questions.

And it is so strange that there's no way to reset the security question by virify the email . So now I still cannot update the Apple Developer Program license agreement

you can login in icloud with your account on a phone(must), then start the two factor verification, use this the two factor verification, you can login to apple id account.

I can't use my apple id to login icloud, because my apple id is not an email address.

How to solve this case?

I was able to overcome this by signing into my iPhone with the developer account details (Apple ID), then next time I tried to login it automatically enabled the 2FA and skipped the security question.