单选题

以下代码的运行结果为：

Question

以下代码的运行结果为：

class Base {
    public:
        Base() {
            echo()
        }
        virtual void echo() {
            printf("Base")
        }
}
  
class Derived:public Base {
    public:
        Derived() {
            echo()
        }
        virtual void echo() {
            printf("Derived")
        }
}
  
int main() {
    Base* base = new Derived()
    base->echo()
    return 0
}

A. Derived Derived Derived

B. Derived Base Derived

C. Base Derived Base

D. Base Derived Derived