下列代码执行后的输出是？（ ）
mylist= [1, 2, 3, 4, 5]
newlist = mylist[1:4]
newlist.append(6)
print(newlist)
[1, 2, 3, 4, 6]
[1, 2, 3, 6]
[2, 3, 4, 6]
[2, 3, 4, 5, 6]