用( )可以反映协差阵所体现的分散程度。 A. <img src="https://static.zxtiku.com/wangke/imgs/topic/e9307b55b6520e98ab67e0c282dbfce4.jpg"/><br/> B. <img src="https://static.zxtiku.com/wangke/imgs/topic/394298650c5b97dc88997aae41f87e0d.jpg"/> C. <img src="https://static.zxtiku.com/wangke/imgs/topic/d949cee78cf7f9e41b4ffa61727dd8fe.jpg"/> D. <img src="https://static.zxtiku.com/wangke/imgs/topic/15421104fb041d95532f0ee02306603d.jpg"/>