下列代码,不存在语法错误的是
选项：

A:class A{ public: A(const A& a){ id = new int(*(a.id)) ;} private: int * id = nullptr; }; int main(){ A a1; A a2 = a1; }
B:class A{ public: A(int i){} A(int i,int j = 3){} }; int main(){ A *a1 = new A(2); }
C:class T { public: T(int ){} }; class A{ public: A(T t){} }; void func(A a){} int main(){ A *a1 = new A(2); }
D:class T { public: T(int ){} }; class A{ public: A(T t){} }; void func(A a){} int main(){ func(2); }