执行下列代码，正确的答案是？（ ）
>>> l=[10,0,1,6,12,8]
>>> l.sort(key=str)
>>> l
[0,1,6,8,10,12]
[0,1,10,12,6,8]
[0,1,10,6,8,12]
[12,10,8,6,1,0]