Consider the following two phase locking protocol. Suppose a transaction $T$ accesses (for read or write operations), a certain set of objects $\{O_1, \dots, O_k\}$. This is done in the following manner: Step 1. $T$ acquires exclusive locks to $O_1, \dots, O_k$ in increasing order of their addresses. Step 2. The required operations are performed. Step 3. All locks are released. This protocol will

Let us analyze the two properties of the given locking protocol:

1. Serializability:

   • The protocol follows strict two-phase locking (2PL) where all locks are acquired before any operations are performed and before any lock is released (all locks released together at the end).

   • Basic Two-Phase Locking (and conservative/rigorous 2PL) guarantees conflict serializability because the lock point of each transaction establishes a serial order without conflict cycles.

2. Deadlock-freedom:

   • Deadlock occurs if there is a circular wait condition in the resource allocation graph.

   • In this protocol, every transaction requests and acquires exclusive locks on objects in a globally predefined linear ordering (i.e., in increasing order of their memory addresses).

   • Imposing a global strict total ordering on resource acquisition prevents circular waiting, thereby guaranteeing freedom from deadlocks.

Hence, the protocol guarantees serializability and deadlock-freedom.

Correct Option: (A)