In Fig. 6.8 which of the following is a regular polygon? All have equal side except (i)

In regular polygon all sides and all angles are equal

In Figure I all sides are not equal.

So it is not regular polygon.

Figure II has all sides and angles are equal.

So figure II is regular polygon

In figure III all sides are not equal.

So it is also not regular polygon.

The figure numbered (iv) is not a regular polygon.

Because in this figure the sides are not equal.