运行下列代码，输出结果是？（ ）
alist=[1,2,3,4,5]
blist=','.join(str(n) for n in alist)
print(blist)
1,2,3,4,5
1 2 3 4 5
[1,2,3,4,5]
"1,2,3,4,5"