Three particles, each of mass $m$ are situated at the vertices of an equilateral triangle $ABC$ of side $l \mathrm{cm}$ (as shown in the figure). The moment of inertia of the system about a line $AX$ perpendicular to $AB$ and in the plane of $ABC,$ in gram ${\mathrm{cm}}^2$ units will be :-

We have a rectangular slab of same thickness. $E, F, G, H$ are the middle point of $AB, BC, CD$ and $AD$ respectively then which of the following axis the moment of inertia will be minimum:-

Four similar point masses (each of mass $m$ ) are placed on the circumference of a disc of mass $M$ and radius $R.$ The $M.I.$ of the system about the normal axis through the centre $O$ will be:-