Consider the following C program (assuming that necessary header files are included and that there are no compilation or execution errors):

int main(int argc, char **argv) { // Main process's PID=42  pid_t pid = fork(); // creates process with PID=11  if (pid == 0) { pid_t pid2 = fork(); // creates process with PID=25  if (pid2 > 0) { sleep(20); exit(0); } else { sleep(10); printf("** ONE ** "); exit(0); } } else { pid_t pid3 = fork(); // creates process with PID=89  if (pid3 == 0) { sleep(20); exit(0); } sleep(10); pid_t pid4 = fork(); // creates process with PID=123  if (pid4 != 0) { sleep(20); printf("** TWO ** "); exit(0); } waitpid(pid3, NULL, 0); exit(0); } sleep(20); exit(0); } 

1 : At what time is ** ONE ** printed to the terminal?

2 : At what time is ** TWO ** printed to the terminal?

3 : What is the PID of the process that prints ** TWO **?

4 : What is the PPID of the process with PID 25?

5 : At what time does the process with PID 89 terminate?

6 : How many children does PID 42 create?

7 : What is the PPID of the last process to exit?

8 : Which processes are alive (i.e., not terminated/zombies) at time 15

9: Give the PID of a process that is a zombie at some point during execution