The compound in question, 2,5,8,11,14,17,20,23,26-nona-oxaoctacosan-28-yl p-(butylamino) benzoate, is known for its activity as an antitussive. Let us explore why this option is the correct answer and evaluate why the other options are incorrect.
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:
Match the following:
(P) Schedule H
(Q) Schedule G
(R) Schedule P
(S) Schedule F2
Descriptions:
(I) Life period of drugs
(II) Drugs used under RMP
(III) List of Prescription Drugs
(IV) Standards for surgical dressing