The radius of gyration of a section of area A and least moment of inertia I about the centroidal axis, is

• A. <img src="/_files/images/civil-engineering/theory-of-structures/86-21-62-1.png">
• B. <img src="/_files/images/civil-engineering/theory-of-structures/86-21-62-2.png">
• C. <img src="/_files/images/civil-engineering/theory-of-structures/86-21-62-3.png">
• D. <img src="/_files/images/civil-engineering/theory-of-structures/86-21-62-4.png">