Chất nào sau đây là đipeptitA.B.C.D.

A.$H_{2}N-C{H}_2-CONH-C{H}_2-C{\left(C{H}_3\right)}_2-COOH$

B.$H_{2}N-C{H}_2-CONH-C{H}_{2}CONH-C{H}_2-COOH$

C.$H_{2}N-C{H}_2-CONH-C{H}_2-C{H}_2-COOH$

D.$C{H}_2-C{H}_2-CONH-CH\left(C{H}_3\right)-COOH$