Which of the following compounds can form a zwitterion?

A zwitterion is a molecule having both a positive and a negative charge but a net charge of zero. Amino acids typically form zwitterions because they contain both an acidic carboxyl group ($-\text{COOH}$) and a basic amino group ($-{\text{NH}}_2$). Glycine (${\text{H}}_2\text{N}-{\text{CH}}_2-\text{COOH}$) exists as ${}^{+}{\text{H}}_3\text{N}-{\text{CH}}_2-{\text{COO}}^{-}$ in neutral aqueous solution.