Match Specific Characters

touch file3.txt file4.txt fileA.txt fileB.txt fileC.txt
ls *.txt
ls file?.txt
ls file[12].txt
ls file[123].txt
ls file[1-3].txt
ls file[AB].txt
ls file[A-C].txt
ls file[!12].txt
ls file[!A-C].txt
ls file[!A].txt
cp file[!12].txt backup