The side AD of the square block ABCD as shown in the given figure is fixed at the base and it is under a state of simple shear causing shear stress and shear strain , where The distorted shape is AB'C'D. The diagonal strain (linear) will be

• A. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/60-380-2.png">
• B. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/60-380-3.png">
• C.
• D. <span class="root">2</span>
• E.