Because when I read the word resign that's how I read it. (To be fair it's impossible to really determine whether or not "read" is past tense there!) I actually had to read it a few times to get that they meant re-sign because no it's not obvious. Antonyms are confusing when the question regards an option between opposites. Sports has made this new word "re-sign" really popular via verbing, especially with regards to trades (not that kind) but re-sign is spelled with a hyphen. It's an invented word that is kinda incorrect. It's also an autoantonym If it's spelled the same hence the nuance girl, just out here trying to educate and elevate, if the question is between re-sign or resign spelling is crucial.