单选题 程序如下所示,该程序的运行结果是: class Dog { String dogname; int age; Dog() { } Dog(String name) { dogname = name; } void bark(int count) { System.out.println(dogname + " bark: " + age); } } public class DogTest2 { public static void main(String[] args) { Dog g1, g2; g1 = new Dog(); g2 = new Dog("two"); g1.dogname = "one"; g2 = g1; g1.age = 10; g2.age = 20; g1.bark(5); } }