Answer-Two transactions T1 and T2 both follow the Two-Phase Locking (2PL) protocol. T1 acquires an exclusiv...

Two-Phase Locking guarantees that resulting schedules are conflict-serializable by controlling when locks may be acquired growing phase and released shrinking phase relative to a single transaction, but it does not, by itself, prevent deadlocks between transactions. The scenario described T1 holding A and waiting for B, while T2 holds B and waits for A is a genuine circular-wait deadlock, and resolving it requires a separate mechanism, such as deadlock detection using a wait-for graph, timeouts, or enforcing a consistent global lock-ordering policy, none of which are inherently provided by 2PL alone.

Question

Two transactions T1 and T2 both follow the Two-Phase Locking (2P

L protocol. T1 acquires an exclusive lock on row A and then requests a lock on row B, while T2 has already acquired an exclusive lock on row B and now requests a lock on row A. What is the most accurate statement about this situation?

A Two-Phase Locking guarantees this situation can never occur, since it enforces a fixed global lock acquisition order between all transactions

B This is a deadlock, since T1 is waiting for a resource held by T2 while T2 is simultaneously waiting for a resource held by T1, and 2PL alone does not prevent this kind of circular wait

C This situation always resolves automatically, because 2PL requires transactions to release all locks immediately after acquiring a new one

D This is not a deadlock, since Two-Phase Locking guarantees strict serializability, which inherently eliminates all circular wait conditions

E Two-Phase Locking will automatically abort T2 as soon as the circular dependency begins forming, without requiring any external deadlock detection mechanism

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Two transactions T1 and T2 both follow the Two-Phase Locking (2P

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