$10)$ Which is not true about interprocess communication $($IPC$)?$

A$)$ There are generally two models of IPC, i$.$e$.$ shared memory and message passing

B$)$ Pipes can be used only in the parent$-$child processes or among multiple threads of a process

C$)$ Message sending need not block the processes

D$)$ Different processes communicating through sockets must have different port numbers