difference bwtween "conceive of to be" vs"conceive of as"

[YidanX684]

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 for private 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,

D,which refers to telephone,it's wrong.
A,conception of is not good as conceived of.right?

BUT as for B,whether "but which has",which can refer to the radio?or what it should refer to?
as for D,whether which can refer to the radio or conversation or the telephone?
as for c,whether it can refer to the radio?

[RonPurewal]

Please don't start new threads for problems that are already on the forum.

marconi-s-conception-of-the-radio-t7377-45.html

Please post these questions on that thread. Thanks.