Which of the following are synchronization tools in Go? (channels, sync.WaitGroup, sync.Mutex, sync.Cond)

In Go, all the listed tools are synchronization mechanisms, but they are used in different scenarios:

• Channels — the primary mechanism for communication and synchronization between goroutines. They allow data transfer and block the sender/receiver until ready.
• sync.WaitGroup — used to wait for a group of goroutines to finish. It allows the main goroutine to wait until all child goroutines complete.
• sync.Mutex — a mutex for protecting critical sections, preventing concurrent access to shared resources.
• sync.Cond — a condition variable that allows goroutines to wait for a specific condition and notify each other when it occurs.

All of them are synchronization tools, but channels are a more idiomatic way in Go for data exchange and synchronization, while sync.* structures provide lower-level control.