给定⼀个简单的类定义如下，（ ）语句在类的外部正确地创建了⼀个 Circle 对象并调⽤了 getArea 函数？
1 class Circle {
2 private:
3 double radius;
4 public:
5 Circle(double r) : radius(r) {}
6 double getArea() {
7 return 3.14 * radius * radius;
8 }
9 };
Circle c = Circle(5.0); c.getArea(c);
Circle c(5.0); getArea(c);
Circle c = new Circle(5.0); c.getArea();
Circle c(5.0); c.getArea();