单项选择题

有如下程序:
#include<iostream.h>
using namespace std;
class TestClass
public:
TestClass ()cout<<"default constructor\n";
TestClass(const TestClass &x)cont<<"copy constructor\n";
TestClass userCode(TestClass b)TestClass c(b);return c;
int main()
TestClass a,d;
cout<<"calling userCode()\n";
d=userCode(

A.;
return 0;
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