单选题 下面Java代码的运行结果是( ). class Penguin { private String name = null; // 名字 private int health = 0; // 健康值 private String sex = null; // 性别 public void Penguin() { health = 10; sex = "雄"; System.out.println("执行构造方法."); } public void print() { System.out.println("企鹅的名字是" + name + ",健康值是" + health + ",性别是" + sex + "."); } public static void main(String[] args) { Penguin pgn = new Penguin(); pgn.print(); } }