哪位能帮忙看看这道语法题，whether or not 能成为正确选项吗？

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 that balloon angioplasty preceded with ultrasound was 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

正确答案是B，可是OG中不是说whether or not这用用法不简洁吗，直接用whether就可以了吗？另外C为什么不对？是不是比较从句没有补出is产生歧义？

Don't think the answer should be B since whether or not should be avoided all the times.

C and D are exactly the same?

I think A should be better.

For B,was needed for determining should be changed to was needed to determine, and is should be changed to was.

但是Longman上对need的解释中有这样的用法

I need glassed for reading.

need 跟for doing是可以接受的。

答案该是c或d中的一个，因为两个是一样的。将其中的一个中的第二个that改成wether,就是正确答案。

其他几个选项都有一定的错误。