Acidic amino acids have two COOH groups and one $N{H}_2$ group per molecule. Choose the pair that are acidic amino acids.

An amino acid is the structural and functional unit of protein and are made up of carbon, hydrogen, oxygen, nitrogen and sometimes sulphur. These are organic acids with a carboxyl group and one amino group. Amino acid acts as a buffer. 
Based on the groups that are present on the side chain of amino acid they are divided into various categories. 
Acidic amino acids are the ones that have a carboxyl group in their side chain for example aspartic acid and glutamic acid.
Basic amino acids are the ones that have a basic group and NH2 in their side chain; for example lysine and arginine.
Simple amino acids are the ones that do not have any functional group in their side chain; for example glycine, valine and alanine.