(单选题, )下面代码的输出结果是（ ） L = [1,2,3,4,5] S1 = ','.join(map(str,L))Print(s1)
A.1,2,3,4,5
B.1,,2,,3,,4,,5
C.[1,,2,,3,,4,,5]
D.[1,2,3,4,5]
正确答案是A