$10.$ What type of passing parameter based on the following code fragment?

class Student $\{$

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

Student s $=$ new Student$($Ali$,21)$;

printData$($s$)$;

$\}$

public void printData$($Student stu$)\{$

System.out.println$($stu$.$toString$())$;

$\}$

$\}$