Correct Option (4)
Let the initial price of the commodity be p.
- After the first increase by k%, the price becomes:

- After the first decrease by k%, the price becomes:

- After the second increase by k%, the price becomes:

- After the second decrease by k%, the final price q becomes:

This expression can be simplified using the algebraic identity
.
Applying this identity to the terms
, we get:
.