The ratio of maximum shear stress to average shear stress of a circular beam, is

• A. <img src="/_files/images/civil-engineering/theory-of-structures/87-21-76-1.png">
• B. <img src="/_files/images/civil-engineering/theory-of-structures/87-21-76-2.png">
• C. <img src="/_files/images/civil-engineering/theory-of-structures/87-21-76-3.png">
• D. <img src="/_files/images/civil-engineering/theory-of-structures/87-21-76-4.png">