Glycylalanine is a dipeptide made of two amino acids. The name indicates glycine ("glycyl") and alanine ("alanine"). Glycine is \(\text{H}_2\text{NCH}_2\text{COOH}\) (side chain is H), and alanine is \(\text{H}_2\text{NCH}(\text{CH}_3)\text{COOH}\) (side chain is \(\text{CH}_3\)). They form glycylalanine: \(\text{H}_2\text{N}-\text{CH}_2-\text{CO}-\text{NH}-\text{CH}(\text{CH}_3)-\text{COOH}\).
Option 1 matches this with glycine and alanine. Other options include valine or leucine, which do not fit.
Thus, the correct answer is option 1.