Which of the following compounds is not an acid anhydride?

• A. <a href="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-acid-anhydrides-q4a.png"><img alt="The following compounds is not an acid anhydride - option a" class="alignnone size-full wp-image-224766" height="109" src="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-acid-anhydrides-q4a.png" width="62"/></a>
• B. <a href="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-acid-anhydrides-q4b.png"><img alt="The following compounds is not an acid anhydride - option b" class="alignnone size-full wp-image-224767" height="62" src="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-acid-anhydrides-q4b.png" width="61"/></a>
• C. <a href="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-acid-anhydrides-q4c.png"><img alt="The following compounds is not an acid anhydride - option c" class="alignnone size-full wp-image-224768" height="85" src="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-acid-anhydrides-q4c.png" width="76"/></a>
• D. <a href="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-acid-anhydrides-q4d.png"><img alt="The following compounds is not an acid anhydride - option d" class="alignnone size-full wp-image-224769" height="51" src="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-acid-anhydrides-q4d.png" width="98"/></a>