单选题 下面程序运行结果为(). class Alpha{ String getType(){return "alpha";} } class Beta extends Alpha{ String getType(){return "beta";} } class Gamma extends Beta{ String getType(){return "gamma";} public static void main(String[] args){ Alpha g1=new Beta(); Alpha g2=new Gama(); System.out.println(g1.getType() + "" + g2.getType());} }