A shot of mass m penetrates a thickness t of a fixed plate of mass M. If the plate were free to move and the resistance supposed to be uniform, which one of the following is the thickness penetrated ?

• A. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/49-1472-1.png">
• B. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/49-1472-2.png">
• C. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/49-1472-3.png">
• D. <img src="/_files/images/civil-engineering/upsc-civil-service-exam-questions/49-1472-4.png">