利用电源的等效变换，则图示电路的电流i为（）。<img src="https://static.zxtiku.com/wangke/imgs/topic/674c9995d3fc7800a59a14adf1c9cbce.jpg"/><br/> A、<img src="https://static.zxtiku.com/wangke/imgs/topic/7e2dedb3a88d74dbeb1ea1ffac6ecf4f.jpg"/><br/> B、<img src="https://static.zxtiku.com/wangke/imgs/topic/ff4b1197f863c342de60ec94933d9c85.jpg"/><br/> C、<img src="https://static.zxtiku.com/wangke/imgs/topic/68a71c824f545dfb73f79c079c741ae0.jpg"/><br/> D、<img src="https://static.zxtiku.com/wangke/imgs/topic/3902a17d32351e7743841b04505645fd.jpg"/>