Fill in the blanks with the help of options, given in the box.
I. In __P__ sketch of the solid, the measurements are kept proportional.
II. A __Q__ polygon has as many lines of symmetry as it has sides.
III. A __R__ is a skeleton-outline of a solid that can be folded to make the solid.
IV. While rectangle is a 2-D figure, __S__ is a 3-D figure.