执行下面Python代码后，输出的结果是？（ ）
t1 = (1, 2, 3, 4, 5, 6, 7)
t2 = ('a', 'b', 'c', 'd', 'e', 'f')
s = t1[2:] + t2[5:2:-1]
print(s)
(3, 4, 5, 6, 7, 'c', 'd', 'e')
(3, 4, 5, 6, 7, 'f', 'e', 'd', 'c')
(3, 4, 5, 6, 'f', 'e', 'd', 'c')
(3, 4, 5, 6, 7, 'f', 'e', 'd')