Moment of inertia of a thin rod

Question

Moment of inertia of a thin uniform rod rotating  about perpendicular axis  passing  through its centre is  I . If  the same rod is bent into a ring and moment  of inertia about its diameter  is I^' . Then the ratio I/ I^' is 

A) 8/3( pie)²

B) 5/3(pie) square   

^{c) 3/ 2( pie) square} 

 

^{D ) 2/3 (pie) square}

Answer 1

Solution........