You should be giving gibberish answers to those anyway. They're probably stored as plaintext, but on the off chance they're not, treat them as a backup password and don't answer the question honestly.
I generate random strings for these and store them in my password manager. On several occasions I've called companies for whatever reason and they've asked these questions to verify my identity. When I say "oh it's a random string let me open my password manager to confirm it" they often reply with "oh it's ok, you're right it's gibberish" and consider me verified.
Just don't answer the questions basically.
Also, you don't need to type gibberish. If your mothers maiden name is Jones, you can enter her maiden name as Steenberger and store that in your password manager.