What is the IUPAC Name of the Following Compound?

Question

What is the IUPAC name of the following compound? 
A) butyl butanoate 
B) propyl butanoate 
C) propanoic anhydride 
D) butanoic anhydride

Accepted Answer

The compound has two butanoic acid groups bonded to each other through an oxygen bridge, making it an anhydride. Therefore, the IUPAC name is butanoic anhydride, which corresponds to choice D.