Assess undergraduate-level understanding of ACID properties (Atomicity, Consistency, Isolation, Durability) and standard transaction isolation levels in relational databases: define each ACID property, explain isolation levels (Read Uncommitted, Read Committed, Repeatable Read, Serializable), identify concurrency anomalies (dirty read, non‑repeatable read, phantom), and analyze short scenarios to select and justify appropriate isolation levels and concurrency control techniques (locking, MVCC) while discussing trade-offs between consistency and performance.