a. Assume the buffer size is 500 bytes and the clock only runs on sleep() call, for the following piece of code, how many seconds will pass before you can see something on the screen? Please justify your answer. int main(int argc, char *argv[]) { while(1) { sleep(1); /* sleep one second */ printf("abcde"); } } b. If the printf() is changed to prinf("abcde "), how many seconds will pass before you can see something on the screen? If the result is different with (a), explain why. c. Following (a), if the following code is inserted before printf(), how many seconds will pass before you can see something on the screen? If the result is different with (a), explain why. setbuf(stdout, NULL)