I have a language-learning app that shows the user a sentence with an extraneous word added that doesn't make sense in the context, and they have to choose which word doesn't belong:
When they tap a word, it marks it with a red X, indicating this is the one that they chose as incorrect.
One user gave feedback that the red X was confusing since it looked like an indication that they answered the question incorrectly.
It seems inherently confusing, because there are two contradictory ideas of "correct" and "incorrect" at the same time, i.e. if the word is incorrect, the user's selection is correct, and vice versa if the word is correct, the user's selection is incorrect.
What is the best way to indicate to a user that they have correctly chosen the incorrect option?