You can make a CAPTCHA plugin, see plugin docs here and captcha section here.
I'm sure somebody made a CAPTCHA plugin that allowed you to write pre-determined questions, which would suit your case very well. But I cannot find it now.
Welcome to the Q&A site for Question2Answer.
If you have a question about Q2A, please ask here, in English.
To report a bug, please create a new issue on Github or ask a question here with the bug tag.
If you just want to try Q2A, please use the demo site.
April 20, 2021: Q2A 1.8.6 released!