What is the greenWidget's inStock value when running this code?

public class Widget $\{$

private int inStock;

public Widget$()\{$

inStock $=10$;

$\}$

public void addInventory$($int amt$)\{$

inStock $=$ inStock $+$ amt;

$\}$

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

Widget greenWidget $=$ new Widget$()$;

greenWidget.addInventory$(15)$;

greenWidget.addInventory$(5)$;

$\}$

$\}$

Group of answer choices

$10$

$5$

$30$

$20$