Which deadlock-handling strategy works by ensuring that at least one of the four necessary conditions for deadlock (such as Hold and Wait) can never occur in the system?

Deadlock Prevention works by structurally ensuring that at least one of the four necessary conditions for deadlock (Mutual Exclusion, Hold and Wait, No Preemption, Circular Wait) can never hold, thereby making deadlock structurally impossible. Deadlock Avoidance instead uses algorithms like the Banker's Algorithm to dynamically avoid unsafe resource-allocation states, Deadlock Detection identifies deadlocks after they occur, Deadlock Recovery deals with resolving a deadlock once detected, and "Deadlock Ignorance" describes an approach (like the Ostrich Algorithm) of assuming deadlocks rarely occur rather than preventing them structurally.