已知嵌套列表matrix = [[1, 2], [3, 4], [5, 6]],下列代码片段中可以正确遍历该列表并求出所有元素总和的是?
matrix = [[1, 2], [3, 4], [5, 6]]
total = 0 for row in matrix: total += row print(total)
total = 0 for row in matrix: for num in row: total += num print(total)
total = 0 i = 0 while i < len(matrix): total += matrix[i] i += 1 print(total)
total = 0 for i in range(len(matrix)): for j in range(len(matrix)): total += matrix[i][j] print(total)