Some of the statements below are true about operating system processes. Which ones are they? i when a process has completed its job it exists either voluntarily or involuntarily ii a process can be terminated by the operating system if, for example, it executed an illegal instruction, referenced a nonexistent memory, or divided by zero iii two parents are needed to create a child process iv when a process switches from running to blocked state, its process counter, stack pointer, memory allocation, and everything else are saved as a process table entry i, ii, and iii ii, iii, and iv ii and iii ii and iv