umm.... That's because that option supercedes the other one... For example, if you look carefully, it doesn't say highschool AND GED but instead it says highschool OR GED.
A big reason why the ged is sometimes called the general equivalency diploma, is becuase those taking it, must score higher than 40 percent of currently graduating highschool seniors.
Therefore, it should be fairly logical to assume, since the GED is equivalent to graduating highschool, that if you have one - the "didn't graduate highschool" option is not for you, no matter how much of a badge of honor it may be.
(also, logic dictates the GED option is more specific, not all dropouts have geds, but all GED holders never finished highschool. )