$1.$ Select the output of the following program:

#include

using namespace std;

void fun$($int &x$,$ int y$,$ int &z$)$

$\{$

$$ x $=10$;

$$ y $=20$;

$$ z $=30$;

$\}$

int main$()$

$\{$

$$ int a $=1$;

$$ int b $=2$;

$$ int c $=3$;

$$ fun$($a$,$ b$,$ c$)$;

$$ cout $<<$ a $<<<<$ b $<<<<$ c;

$$ return $0$;

$\}$

a$.123$

b$.102030$

c$.10230$

$1203$