Which of the following figure correctly shows approximate order of difficulty?

• A. <a href="https://www.sanfoundry.com/wp-content/uploads/2015/10/data-science-questions-answers-analysis-experimental-design-q9a.png"><img alt="The figure correctly shows approximate order of difficulty - option a" class="alignnone size-full wp-image-179363" height="300" src="https://www.sanfoundry.com/wp-content/uploads/2015/10/data-science-questions-answers-analysis-experimental-design-q9a.png" width="292"/></a>
• B. <a href="https://www.sanfoundry.com/wp-content/uploads/2015/10/data-science-questions-answers-analysis-experimental-design-q9b.png"><img alt="The figure correctly shows approximate order of difficulty - option b" class="alignnone size-full wp-image-179364" height="300" sizes="(max-width: 300px) 100vw, 300px" src="https://www.sanfoundry.com/wp-content/uploads/2015/10/data-science-questions-answers-analysis-experimental-design-q9b.png" srcset="https://www.sanfoundry.com/wp-content/uploads/2015/10/data-science-questions-answers-analysis-experimental-design-q9b.png 300w, https://www.sanfoundry.com/wp-content/uploads/2015/10/data-science-questions-answers-analysis-experimental-design-q9b-150x150.png 150w" width="300"/></a>
• C. <a href="https://www.sanfoundry.com/wp-content/uploads/2015/10/data-science-questions-answers-analysis-experimental-design-q9c.png"><img alt="The figure correctly shows approximate order of difficulty - option c" class="alignnone size-full wp-image-179365" height="300" src="https://www.sanfoundry.com/wp-content/uploads/2015/10/data-science-questions-answers-analysis-experimental-design-q9c.png" width="297"/></a>
• D. All of the mentioned