Can you name the main types of collections that support parallel work and are safe under concurrency?

In C#, the following main collection types from the System.Collections.Concurrent namespace are used to ensure parallel operation and safety during competition:

• ConcurrentDictionary<TKey, TValue> — thread-safe dictionary.
• ConcurrentQueue<T> — thread-safe queue.
• ConcurrentStack<T> — thread-safe stack.
• ConcurrentBag<T> — collection for storing objects without a specific order, optimized for parallel access.

These collections allow multiple threads to safely add and retrieve elements without the need for external synchronization.