(a) a stone, (b) a train, (c) a five-rupee coin.
Explanation: Inertia is directly proportional to mass, meaning the object with more mass has more inertia.
(a):
A stone is denser than a rubber ball of the same size, so the stone has more mass and therefore more inertia.
(b):
A train is significantly heavier than a bicycle, resulting in greater inertia for the train.
(c):
A five-rupee coin is heavier than a one-rupee coin, so it has more inertia.