If n is the ratio of internal and external diameters of a hollow shaft, the ratio of the weight of the hollow shaft and that of solid shaft of same strength, will be

• A. <img src="/_files/images/civil-engineering/strength-of-materials/134-6.150-1.png">
• B. <img src="/_files/images/civil-engineering/strength-of-materials/134-6.150-2.png">
• C. <img src="/_files/images/civil-engineering/strength-of-materials/134-6.150-3.png">
• D. <img src="/_files/images/civil-engineering/strength-of-materials/134-6.150-4.png">