The information is stored on Adaxes backend (which is ADAM or AD LDS depending on the operating system). By default, only Adaxes default service administrator (the user that you specified during Adaxes installation) can access the ADAM / AD LDS instance used by Adaxes.
The questions that were used to enroll a user are stored unencrypted. As for the answers, the actual answers are not stored. Adaxes stores only hashes of the answers, and when a user tries to self-reset a password, Adaxes compares the hashes of the answers.