Can you please make the captcha easier for humans?
Why not to use such simple Captcha like this:
"I am Captcha and I will pick a secret word. You are user and you are to guess what word it is. If your guess is not right, I will give you a hint. You have only 3 attempts."
Then, interaction will be started and user will find this secret word in 3 attempts at most.
C(aptcha):Guess a word. It is red.
C:No. It is above.
questions = [..., ["sun":"It is red", "It is above", "It is celestial body"], ...]