Final answer:
A reversible process is one in which the system and environment can return to their original states, while an irreversible process does not return to its original state. Irreversible processes depend on path and occur spontaneously in one direction only.
Step-by-step explanation:
A reversible process is one in which both the system and its environment can return to exactly the states they were in by following the reverse path. On the other hand, an irreversible process depends on path and does not return to its original state.
For example, the expansion of a puff of gas introduced into a vacuum chamber is an irreversible process. The gas molecules could theoretically return to the corner where they were initially introduced, but in reality, they never do. This is because irreversible processes are spontaneously in one direction only.
Therefore, the matching for the given statements would be:
A. Irreversibility → Spontaneously in one direction only
B. Irreversible process → Depends on path
C. Reversible process → Both the system and environment can return to their original states