Also regarding choice D (I have noticed the tense error and the redundancy of "that were cast", and have corrected them in the below sentence):
#3 4 million to 6 million of the 100 million votes cast were not counted in the 2000 United States presidential election.
In #3, "in the 2000 United States presidential election" definitely modifies the verb "were not counted". In #1,"in the 2000 United States presidential election" modifies the the whole following clause . I always think that prepositional modifiers that modify the the whole following clause are , in essence, the same as prepositional modifiers that modify the verb in that clause. Technically, I think they are the same. So, from that perspective, why #1 differs from #3 , and #1 is meaningly correct while #3 is not?
Thanks in advance.
I have no idea how to respond in general terms, so I'll just give you an example that is easier to understand.
1/
Everyone I knew was tanning at the beach.2/
At the beach, everyone I knew was tanning.You see the difference, right?
In #1, "everyone I knew" is
not qualified by "at the beach"... because we haven't said "at the beach" yet. (It's not reasonable to expect the reader to understand restrictions that haven't yet been stated!)
So, #1 says that
everyone I knew"”like, literally, every single person with whom I was acquainted at all"”was hanging out in the sun.
#2 is talking only about familiar people
among people who were at the beach"”a much more reasonable meaning.
This example is easier to understand because both meanings actually make sense (although #1 is a bit crazy).
But, just make an analogy. Your #3, like #1 about the beach, is speaking of "the votes cast" as though they were just a thing, independent of any particular election (like "everyone I knew""”independent of location). Doesn't work.