3．一个理想变压器，原线圈和副线圈的匝数分别为n₁和n₂，正常工作时输入和输出的电压、电流、功率分别为U₁和U₂、I₁和I₂、P₁和P₂，已知n₁＞n₂，则                                        

A．U₁＞U₂，P₁＜P₂                                                                B．P₁＝P₂ ，I₁＜I₂，

C．I₁＜I₂，U₁＞U₂                                                                     D．P₁＞P₂，I₁＞I₂