求教OG12 SC106

kadin5568576

106.Marconi's conception of the radio was as a substitute
for the telephone, a tool for private conversation:
instead, it is precisely the opposite, a tool for
         communicating with a large, public audience.


(A)Marconi's conception of the radio was as a
substitute for the telephone, a tool for private
conversation; instead, it is

(B)Marconi conceived of the radio as a substitute
for the telephone, a tool for private
conversation, but which is

(C)Marconi conceived of the radio as a tool for
private conversation that could substitute for the
telephone; instead, it has become

(D)Marconi conceived of the radio to be a tool
forprivate conversation, a substitute for the
telephone, which has become

(E)Marconi conceived of the radio to be a
substitute for the telephone, a tool for private
conversation, other than what it is,
为什么C中的it不会有指代问题，我觉得it的指代也不是很清楚，可以指代ratio也可以指代the telephone，而B中的which会有指代不清的问题
基础不好，虚心的向NN们请教

liberzephyr

看到it觉得可能考代词指代，但是看了选项发现所有的it都只同一个东西，很有可能it是对的
再看原文的意思：本来想做私人用途，后来却做了大众传媒
这里想说表示转折关系的两间事，后半部分用表示转折的独立句子比定语从句要好

kadin5568576

谢谢liberzephyr ，为什么表示转折的独立句子比定语从句要好呢，是这种情况就不选定语从句吗？是因为but之后的句子表示的是一种并列关系吗，表示他们地位平等，而定语从句只是一个修饰语吗？