执行以下程序，输出结果为（）
l = [] for i in range(2): r = [1]* 2 l.append(r) l[0][0] = 2 print(l)
[[2,1], [1,1]]
[[2,1], [2,1]]
[[2, [1]], [[1], [1]]]
[[2, [1]], [2, [1]]]
