Đun nóng chất H2N–CH2–CONH–CH(CH3) –CONH–CH2–COOH trong

A. H₂N–CH₂–COOH; H₂N–CH₂–CH₂–COOH

B. H₂N–CH₂–COOH; H₂N–CH(CH₃) –COOH

C. $$\begin{gathered} H_3{N}^{+}-C{H}_2-COOHC{l}^{-}; \\ {H}_2{N}^{+}-C{H}_2-C{H}_2-COOHC{l}^{-} \end{gathered}$$

D. $$\begin{gathered} H_3{N}^{+}-C{H}_2-COOHC{l}^{-}; \\ {H}_2{N}^{+}-CH\left(C{H}_3\right)-COOHC{l}^{-} \end{gathered}$$