Which of the following code snippet represents a Singleton design pattern implementation?

Select one:

public class PrintSpooler $\{$

private PrintSpooler INSTANCE $=$ new PrintSpooler$()$;

private PrintSpooler $()\{\}$

public static PrintSpooler getInstance$()\{$

return INSTANCE;

$\}$

$\}$

public class PrintSpooler $\{$

public PrintSpooler INSTANCE $=$ new PrintSpooler$()$;

public PrintSpooler $()\{\}$

public static PrintSpooler getInstance$()\{$

return INSTANCE;

$\}$

$\}$

public class PrintSpooler $\{$

private static final PrintSpooler INSTANCE $=$ new PrintSpooler$()$;

private PrintSpooler $()\{\}$

public static PrintSpooler getInstance$()\{$

return INSTANCE;

$\}$

$\}$

public class PrintSpooler $\{$

private final PrintSpooler INSTANCE $=$ new PrintSpooler$()$;

private PrintSpooler $()\{\}$

public static PrintSpooler getInstance$()\{$

return INSTANCE;

$\}$

$\}$