【单选题】
同步发电机直轴电抗<imgsrc="http://wljy.whut.edu.cn:80/uploadfiles/kindeditorAttached/image/20191121/20191121093404_378.png"alt=""/>三者之间的大小关系为（）。
①
<imgsrc="http://wljy.whut.edu.cn:80/uploadfiles/kindeditorAttached/image/20191121/20191121095321_129.png"alt=""/>
②
<imgsrc="http://wljy.whut.edu.cn:80/uploadfiles/kindeditorAttached/image/20191121/20191121095408_167.png"alt=""/>
③
<imgsrc="http://wljy.whut.edu.cn:80/uploadfiles/kindeditorAttached/image/20191121/20191121095350_584.png"alt=""/>