题目4单选题
已知 DataFrame df,要对其进行按列排序(升序),以下正确的是A. df.sort(by = list(df.columns), axis = 1, ascending = True)B. df.sort_values(by = list(df.columns), ascending = True)C. df.sort_index(axis = 1, ascending = True)D. df.sort(columns = list(df.columns), ascending = True)