What is concurrency control and what synchronization primitives are commonly used?

• A. Locks, mutexes, semaphores, monitors, and condition variables.
• B. Poiners, arrays, linked lists, trees.
• C. Memory redundancy, caching, and prefetching strategies.
• D. Random number generators, hashing, and encryption.

Answer: (A)

Concurrency control is about coordinating access to shared resources so multiple tasks can run at the same time without interfering with each other. The synchronization primitives that are most commonly used for this purpose include locks (often called mutexes) to ensure mutual exclusion, semaphores to manage access to a finite number of resources or to signal between tasks, monitors as higher-level constructs that combine data and the procedures that operate on it with built-in mutual exclusion, and condition variables to let threads wait for certain conditions and wake up when those conditions occur. This combination—locks, mutexes, semaphores, monitors, and condition variables—is exactly what enables safe coordination in concurrent programs.

Other options describe things like data structures (pointers, arrays, linked lists, trees), memory performance techniques (caching, prefetching), or cryptographic tools (encryption, hashing, random number generation). Those are not about coordinating or synchronizing concurrent tasks, so they don’t fit the concept of concurrency control.