Which is an example of a Copy Constructor?

Question $9$ options:

public class Apple

$\{$

String type;

String color;

public Apple$()$

$\{$

type $=$ "Granny Smith";

color $=$ "Green";

$\}$

$\}$

public class Apple

$\{$

String type;

String color;

public Apple$($String type, String color$)$

$\{$

this.type $=$ type;

this.color $=$ color;

$\}$

$\}$

public class Apple

$\{$

String type;

String color;

public Apple$($String color$)$

$\{$

type $=$ "Granny Smith";

this.color $=$ color;

$\}$

$\}$

public class Apple

$\{$

String type;

String color;

public Apple$($Apple a$)$

$\{$

this.type $=$ a$.$type;

this.color $=$ a$.$color;

$\}$

$\}$