Which of the following is unary phase diagram?

• A. <a href="https://www.sanfoundry.com/wp-content/uploads/2017/07/materials-science-questions-answers-unary-phase-diagrams-q10a.png"><img alt="The following is unary phase diagram - option a" class="alignnone size-full wp-image-172947" height="169" src="https://www.sanfoundry.com/wp-content/uploads/2017/07/materials-science-questions-answers-unary-phase-diagrams-q10a.png" width="300"/></a>
• B. <a href="https://www.sanfoundry.com/wp-content/uploads/2017/07/materials-science-questions-answers-unary-phase-diagrams-q10b.png"><img alt="The following is unary phase diagram - option b" class="alignnone size-full wp-image-172948" height="202" src="https://www.sanfoundry.com/wp-content/uploads/2017/07/materials-science-questions-answers-unary-phase-diagrams-q10b.png" width="216"/></a>
• C. <a href="https://www.sanfoundry.com/wp-content/uploads/2017/07/materials-science-questions-answers-unary-phase-diagrams-q10c.png"><img alt="The following is unary phase diagram - option c" class="alignnone size-full wp-image-172949" height="244" src="https://www.sanfoundry.com/wp-content/uploads/2017/07/materials-science-questions-answers-unary-phase-diagrams-q10c.png" width="271"/></a>
• D. <a href="https://www.sanfoundry.com/wp-content/uploads/2017/07/materials-science-questions-answers-unary-phase-diagrams-q10d.png"><img alt="The following is unary phase diagram - option d" class="alignnone size-full wp-image-172950" height="224" src="https://www.sanfoundry.com/wp-content/uploads/2017/07/materials-science-questions-answers-unary-phase-diagrams-q10d.png" width="260"/></a>