OG10-15 问个很菜的问题

15. In his research paper, Dr. Frosh, medical director of the Payne Whitney Clinic, distinguishes mood swings. which may be violent without their being grounded in mental disease, from genuine manic-depressive psychosis.

(A)  mood swings, which may be violent without their being grounded in mental disease, from genuine manic-depressive psychosis

(B)  mood swings, perhaps violent without being grounded in mental disease, and genuine manic-depressive psychosis ,

(C)  between mood swings, which may be violent without being grounded in mental disease, and genuine manic-depressive psychosis

(D)  between mood swings, perhaps violent without being grounded in mental disease, from genuine manic-depressive psychosis

(E)  genuine manic-depressive psychosis and mood swings, which may be violent without being grounded in mental disease

B选项中perhaps violent without being grounded in mental disease是什么结构呢？ 插入语吗？怎么是形容词呢   修饰前面就近的名词吗 ？ 
     

谢谢各位啦~~