I agree with many others that nchar(1) should be the correct answer because I am under the impression that varchars store an additional 2 bytes of data in the background to indicate the length of the data - so therefore Varchar(1) uses 3 bytes if it contains a byte of data and 2 bytes if the field was null or empty. I remember having discussions about the sensible minimum field length for varchar fields and when chars should be used instead to store least data. I could be wrong though...