Given the following code:

public class Computer $\{$

private static int counter$=0$;

private int computerID$=$assignID$()$;

private int assignID$()\{$return $++$counter; $\}$

public static void main$($String$[]$ args$)\{$

Computer compl$=$new Computer$()$;

system.out.println$($x: Computer.counter$)$;

$\}$

$\}$

a$.$ calling the statement System.out.printIn$($Computer$.$counter$)$; reflects the total number of Computer objects created

b$.$ calling the statement System.out.printIn$($Computer$.$counter$)$; is invalid

c$.$ calling the statement System.out.printIn$($Computer$.$counter$)$; will always print out $0$ on screen

d$.$ calling the statement System.out.printIn$($Computer$.$counter$)$; will cause the compiler to report an error