单选题 以下程序的运行结果是( ).#include <stdio.h>int fun1(int x){ return x*x;}int fun2(int x, int y){ double a,b; a=fun1(x); b=fun1(y); return(a+b);}void main(){ double c; c=fun2(2.1,4.2); printf("%10.0lf\n",c);}