Quiz keeps saying "Invalid Answer"

Excuse me if this has already been asked and answered. I looked for it but couldn't find it.

I've created a quiz slide with multiple questions on it, following the excellent tutorial at https://www.articulate.com/support/storyline/how-to-evaluate-multiple-fill-in-the-blanks-on-the-same-slide.

No matter what I do, when I preview the slide and fill in the two text fields, I always get "Invalid Answer: You must complete the question before submitting." I even tried setting the "Correct" button to selected when the submit button was hit with no conditions at all, but even that didn't work. I would really appreciate some help!

I'm attaching the file. (I deleted the file after Wendy gave me the answer.)