[tcpip-unp] consider client-server model. which one of the following choices is not correct? there are three main classes of servers: synchronous, iterative, and concurrent. iterative server iterates through each client, handling it one at a time. concurrent server handles multiple clients at the same time. a concurrent server may spawn a child process with fork to serve a client. a concurrent server with a pool of threads may serve a client with a thread from the pool.