What does the following function print for $n1=12$ and $n2=15?$

def div$($n$1,$ n$2)$:

if $n1n2==0$ :

return $n2$

else:

return div$(n2,n1\%n2)$

print $($div $(12,15))$

a$.12$

b$.15$

c$.3$

d$.9$