Which one among the following carbocations has the longest half-life?

• A. <a href="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-reaction-intermediates-q2a.png"><img alt="The following carbocations has the longest half-life - option a" class="alignnone size-full wp-image-224282" height="69" src="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-reaction-intermediates-q2a.png" width="100"/></a>
• B. <a href="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-reaction-intermediates-q2b.png"><img alt="The following carbocations has the longest half-life - option b" class="alignnone size-full wp-image-224283" height="93" src="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-reaction-intermediates-q2b.png" width="140"/></a>
• C. <a href="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-reaction-intermediates-q2c.png"><img alt="The following carbocations has the longest half-life - option c" class="alignnone size-full wp-image-224284" height="100" src="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-reaction-intermediates-q2c.png" width="141"/></a>
• D. <a href="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-reaction-intermediates-q2d.png"><img alt="The following carbocations has the longest half-life - option d" class="alignnone size-full wp-image-224285" height="56" src="https://www.sanfoundry.com/wp-content/uploads/2018/08/organic-chemistry-questions-answers-reaction-intermediates-q2d.png" width="104"/></a>