有Python程序段如下：
tup=("python","c++","scratch") a=tup[0] b=tup[1] c=tup[2] tup1=(c,b,a) print(tup1)
程序运行后，输出的结果是？（ ）
('scratch', 'c++', 'python')
('python', 'scratch', 'c++')
('scratch', 'python','c++')
( 'c++','python','scratch')