对于以下程序, Customer 对象在第几行变为持久化状态?(单选) Customer customer=new Customer(); //line1 customer.setName(\”Tom\”); //line2 Session session1=sessionFactory.openSession(); //line3 Transaction tx1 = session1.beginTransaction(); //line4 session1.save(customer); //line4 tx1.commit(); //line5 session1.close(); //line6