Who do you think will ____ ____ this film?

如图9-7-13所示的装置中，所有部件都静止时，小磁针亦静止于如图所示的位置。在下述四种情况下，小磁针发生偏转的是（   ）

图9-7-13

                                                                                                                     钱塘湖春行
                                                                                                                      唐 白居易
                                                                                                     孤山寺北贾亭西，水面初平云脚低。
                                                                                                    几处早莺争暖树，谁家新燕啄春泥。
                                                                                                    乱花渐欲迷人眼，浅草才能没马蹄。
                                                                                                    最爱湖东行不足，绿杨阴里白沙堤。