We've had our interview after 7 months of being married to my US citizen wife. after a month I receive my GC which i checked for names, bday etc. i thought everything is ok even if it says there that the validity is 10 years. the category says "B20". I passed everything off coz i thought that everything is just the norm. Then I read here in this forum that it's not. Any info on this? Is this really a typo error? what's a B20 category? Please, please help.