Which statement correctly defines ACID properties in databases?

Which statement correctly defines ACID properties in databases?

• A. Durability, Availability, Integrity, and Privacy Describe Transactional Guarantees
• B. Atomicity, Consistency, Isolation, Durability Describe Reliable Transactions
• C. Atomicity, Consistency, Isolation, Durability Are Irrelevant to Transactions
• D. Atomicity, Concurrency, Integrity, Durability Describe User Access Control

Answer: (B)

ACID defines four guarantees that make database transactions reliable: Atomicity, Consistency, Isolation, Durability. Atomicity means a transaction’s operations are all-or-nothing—if any part fails, the entire transaction is rolled back. Consistency ensures that each transaction takes the database from one valid state to another, preserving all integrity constraints. Isolation means concurrent transactions don’t interfere with each other; each appears to run independently. Durability means once a transaction commits, its effects persist even if the system crashes, typically thanks to persistent storage and logging. The statement that lists these four properties and frames them as describing reliable transactions matches this standard understanding. Other options mix in unrelated concepts (like Availability or Privacy) or misuse terms (such as Concurrency or claiming these properties are irrelevant), so they don’t fit ACID as typically defined.

ACID defines four guarantees that make database transactions reliable: Atomicity, Consistency, Isolation, Durability. Atomicity means a transaction’s operations are all-or-nothing—if any part fails, the entire transaction is rolled back. Consistency ensures that each transaction takes the database from one valid state to another, preserving all integrity constraints. Isolation means concurrent transactions don’t interfere with each other; each appears to run independently. Durability means once a transaction commits, its effects persist even if the system crashes, typically thanks to persistent storage and logging.

The statement that lists these four properties and frames them as describing reliable transactions matches this standard understanding. Other options mix in unrelated concepts (like Availability or Privacy) or misuse terms (such as Concurrency or claiming these properties are irrelevant), so they don’t fit ACID as typically defined.