Which of the following compounds can form a zwitter ion?

The molecule which forms zwitter ion is glycine.

Every zwitterion has an isoelectric point (pI). The isoelectric point is the pH at which a zwitterion is uncharged. The pH can affect the charge of a molecule by introducing protons (H⁺). The amino group of an amino acid is a very effective proton acceptor, so is considered to be basic.