单项选择题

以下程序执行后的输出结果是
#include <iostream>
using namespace std;
void try(int,int,int,int);
int main ()

int x,y,z,r;
x =1 ;
y = 2;
try(x,y,z,r);
cout<<r<<endl;
return 0;

void try(int x,int y,int z,int r)

z = x+y;
x = x*x;
y = y*y;
r = z+x+y;

A.18
B.9
C.10
D.不确定