Rotational symmetry means if we turn an object round it will look same.
Figure P has order of rotational symmetry 4 because it has four ends and if we rotate it in 90o it will look same.
Figure Q has order of rotational symmetry 3 because it is an equilateral triangle and if we rotate it in a fixed angle then it will look same.
Figure R has order of rotational symmetry 2 because it is a kite and its diagonal intersect at 90o.
Figure S has order of rotational symmetry 5 because it is a pentagon whose all sides are equal and if we rotate it in any angle from a fixed point it will look same.
Hence, the answer is (P) → (iv), (Q) → (iii), (R) → (ii), (S) → (i)