The . . . . . . . . property states that the system must have a mechanism to recover from committed transactions should that be necessary.

Solution (By Examveda Team)

Option A: atomicity. Atomicity ensures that a transaction is treated as a single, indivisible unit. This means that either all operations in a transaction are completed successfully, or none are applied at all. Atomicity does not directly relate to recovery mechanisms for committed transactions.

Option B: consistency. Consistency ensures that a transaction brings the system from one valid state to another, maintaining all predefined rules and constraints. While consistency is vital for the integrity of data, it does not specifically address recovery from committed transactions.

Option C: isolation. Isolation ensures that transactions operate independently of one another, meaning the intermediate state of a transaction is not visible to other transactions. Although isolation helps maintain stability during concurrent transactions, it does not pertain to recovery mechanisms for committed transactions.

Option D: durability. Durability guarantees that once a transaction has been committed, it will remain so, even in the event of a system failure. This property ensures that the system has mechanisms in place to recover committed transactions, preserving their effects even after a crash or error.

Conclusion: The correct answer is Option D: durability, as it specifically relates to the requirement for a system to have mechanisms to recover from committed transactions if necessary.