A dipeptide, “x”, on complete hydrolysis gives “y” and “z”; “y” on treatment with aqueous HNO$_2$, produces lactic acid. On the other hand, “z” on heating gives the following cyclic molecule. 
Based on the information given, the dipeptide X is:
| List - I | List - II |
|---|---|
| A) Morphine | IV) Pain killer |
| B) Cannabinoids | V) Dopamine |
| C) Cocaine | I) Cardiovascular system |
| D) Benzodiazepines | II) Tranquilizers |