The correct option is A Serine
The amino acid refers to the group of organic molecules that consist of a basic amino group (−NH2), an acidic carboxyl group (−COOH), and an organic R group (or side chain) that is unique to each amino acid. The amino acids differ from each other in the particular chemical structure of their R group and on the basis of the chemical properties of the R-group chain these are broadly classified as hydrophobic and hydrophilic. The Hydroxyl amino acids are
hydrophilic, polar and uncharged. Serine is the amino acid's with its R group with a hydroxyl group attached to a CH2 group.