Hi there!
The correct option is C. there is a spelling mistake. The red wavy line indicates that a word was spelled incorrectly, sometimes though this function does not recognize the word it can mark it as incorrect even when it is not, in which case you can right-click the marked word and add it to your computer's internal word dictionary. Right-clicking an incorrectly spelled word will also give a short list of words that are similar to the one you are trying to spell, clicking on one of the given words will automatically change the marked word to the one you chose.
-Your friend, ASIAX
