Can we please underline the dang-on question!!! God Dang it dude. I can't stand when people do this.
8.A recording system was so secretly installed and operated in the Kennedy Oval Office that even Theodore C. Sorensen, the White House counsel, did not know it existed.
(A) A recording system was so secretly installed and operated in the Kennedy Oval Office that
"A recording system was installed ..in the oval office"
"A recording system was operated .. in the oval office"
We have parallelism.
A recording system was so secretly installed and operated in the Kennedy Oval Office that Blah Blah did not know about it
Parallelism in the "So X, That Y". The idiom is being correctly used.
"So Secretly". How was the system installed? Ah! Secretly. It is an adverb, because its modifying a verb. Remember if it modifies anything but a noun, its an adverb.
(B) So secret was a recording system installation and operation in the Kennedy Oval Office
Does not use the idiom correctly, we are missing "That" in the "So X, That Y". If you don't know the idiom, now you do.
But also notice the sentence does not make any sense. "So secret was a recording system" ??? What??
As soon as you read this cross it out. Don't even waste your time reading the entire sentence.
(C) It was so secret that a recording system was installed and operated in the Kennedy Oval Office
OMG really?? "It was so secret that a recording system was installed" ???? Come on please, don't tell me some of you fell for this. Besides the fact the sentence is passive, even if we rearranged the sentence to make it active it would still be wrong. "It [[a recording system]] was so secret that a recording system ". A recording system was "so secret"?? Notice how we repeated the same noun twice in literally a few words apart. X was so secret that X blah blah blah. Couldn't we have just said "X was Blah Blah, That Blah Blah"? Did we have to repeat the same noun twice?? Come on folks. Please.
Not to mention, the sentence is missing "that" in the "So X, That Y"
(D) A recording system that was so secretly installed and operated in the Kennedy Oval Office
" A recording system that..". WRONG!! OMG we have "so secretly" being used incorrectly again.
Folks it should be "The recording system was so secretive, that it went undetected"
(E) Installed and operated so secretly in the Kennedy Oval Office was a recording system that
Passive voice. "installed .. was a recording a system". "so secretly" is incorrectly used once more.