So we are all left guessing as to which incorrect answer is a typing error.
I guessed that it was the 3rd option because it is eminently sensible to require that saledate not be null if saleid isn't, and saleid is the primary key, so maybe shipdate in that option was an mistake for saledate, especially as a shipdate might well be null for some time after a slae has been made and an entry created in this table. But the error was in a different option and involved both altering a nonexistent column and a syntactically invalid GO.
So the last two days of the year both have questions where it's impossible to get the answer except by pure guesswork. Not a good end to the year, or to the week.
Anyway, happy new year, Steve.