求教XDF蓝皮书上一道题

Researchers agreed that the study of new treatments for heart attack patients was extremely important but more research was needed to determine that balloon angioplasty preceded with ultrasound was or was not any better for heart attack patients than the balloon procedure by itself.

A.more research was needed to determine that balloon angioplasty preceded with ultrasound was or was not any better for heart attack patients than
B.more research was needed for determining whether or not balloon angioplasty preceded by ultrasound is any better for heart attack patients than is
C.that more research was needed to determine whether balloon angioplasty preceded by ultrasound is any better for heart attack patients than
D.that more research was needed to determine that balloon angioplasty preceded with ultrasound was any better for heart attack patients than
E.that more research was needed for determining that balloon angioplasty preceded by ultrasound is or is not any better for heart attack patients than is

书上的答案为B，但whether or not不是说永远错误吗？我感觉答案为C，请帮忙分析，谢谢！

LZ有没有觉得XDF补充材料越做越晕阿??

很久在ＣＤ上看到一篇欧洲考区Ｎ人对ＧＭＡＴ的心经总结，他说wether or not不一定是永远错，当时看了觉得迷惑，因为我从来都没有遇到一道题wether or not不错的，如果这位Ｎ人的总结正确，那么只能说明wether or not不是正确性错误，是有效性错误。这道题的考点在对称平行结构，than前后２个句子必须对称，Ａ的than后没有be动词，非常明显的不对称的标志，这个考点在ＯＧ里也出现过很多次。如果考点是wether or not，一般其他的选项会有if的出现．

愚见仅供参考