Suppose server and client are communicating with each other, and both are working at a different speed. Which of the following data structure is best suited for synchronization?

The best data structure for synchronization in a scenario where a server and client are communicating at different speeds would be a Queue.

Here's why, step by step:

1. A Queue is a First-In-First-Out (FIFO) data structure. This means that the first element that gets added to the queue is the first one to be removed.

2. In the context of a server-client communication, the server could be thought of as producing data and the client as consuming it. If the server is producing data at a faster rate than the client is consuming it, a queue can be used to store the data temporarily.

3. The server adds data to the end of the queue (enqueue operation) as it produces it. The client removes data from the front of the queue (dequeue operation) as it processes it.

4. This way, even if the server and client are working at different speeds, no data is lost. The queue ensures that all data produced by the server is eventually processed by the client in the order it was produced.

5. Additionally, if the queue becomes full (indicating that the server is producing data much faster than the client can handle), the server can be made to wait or slow down. Similarly, if the queue is empty (the client is faster), the client can be made to wait for the server to produce more data.

6. Therefore, a queue provides a simple yet effective way to synchronize data transfer between a server and client working at different speeds.