That shouldn't be an option and isn't in the system. If you come across it again can you make a screenshot and post it here?
I just had it, I didn't realise I should have taken a screenshot (and sadly I have no idea how to post screenshots here when using the app).
You posted it on another sentence so I'll include this also here: https://www.mediafire.com/view/9z9pqiaep9trr8l
We have no control over what words you are able to select in the app. The only thing we are able to do is make sure that (only) correct answers are available. I assume there is an algorithm that then selects a few other words at random along with the correct words.
How do we translate the following then : "Is he at work ?" Is it "Is hij aan het werk ?"