The correct answer is option 4 - a cricket ball. Inertia refers to the resistance of an object to changes in its state of motion. It is directly related to the mass of an object, with objects that have more mass having greater inertia.

In this case, a cricket ball is likely to have the maximum inertia compared to the other options. This is because a cricket ball has a much larger mass compared to the other objects listed - an atom, a molecule, and a one-rupee coin.

While atoms and molecules are extremely small and have negligible mass compared to a cricket ball, a one-rupee coin also has a significantly smaller mass.

A cricket ball, on the other hand, is relatively larger and heavier, making it harder to change its state of motion. This means that it has a greater resistance to coming to a stop or changing its direction compared to the other options.

Therefore, a cricket ball has the maximum inertia among the given options.