Which explanation about a system call is not correct? Justify your choice.

A$.$ The$$system call$$provides an interface between the operating system and its processes.

B$.$ Every system call has a library procedure that the user program calls. This procedure puts the parameters of the system call into the register and then issues a$$TRAP instruction, which is a protected procedure call to start the operating system.

C$.$ Every system call has a library procedure that the user program calls. Although this library procedure does not hide the TRAP instruction details, it makes the system call appear as an ordinary procedure call.

D$.$ System calls can be grouped roughly into five major categories: process control, file management, device management, information maintenance, and communication