The radius of gyration of a uniform rod of length $l$ about an axis passing through a point $\frac{l}{4}$ away from the centre of the rod and perpendicular to it is:

$A$ circular disc is to be made by using iron and aluminium,so that it acquires maximum moment of inertia about its geometrical axis. This is possible with:

Four point masses,each of mass $m$,are fixed at the corners of a square of side $\ell$. The square is rotating with angular frequency $\omega$,about an axis passing through one of the corners of the square and parallel to its diagonal,as shown in the figure. The angular momentum of the square about this axis is $.......m\ell^2 \omega$.

The moment of inertia of a uniform rectangular plate about an axis passing through its center and parallel to its length $(l)$ is ($b =$ width of the rectangular plate):

Two circular discs $A$ and $B$ are of equal masses and thickness but made of metals with densities ${d_A}$ and ${d_B}$ $({d_A} > {d_B})$. If their moments of inertia about an axis passing through their centres and normal to the circular faces are ${I_A}$ and ${I_B}$ respectively,then:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A$: Moment of inertia of a circular disc of mass $M$ and radius $R$ about $X, Y$ axes (passing through its plane) and $Z$-axis which is perpendicular to its plane were found to be $I_{x}, I_{y}$ and $I_{z}$ respectively. The respective radii of gyration about all the three axes will be the same.
Reason $R$: $A$ rigid body making rotational motion has fixed mass and shape.
In the light of the above statements,choose the most appropriate answer from the options given below: