tallynik wrote:With respect to orginal question how is there a number problem using "IT" ie. with E. "IT" does not refer to vacations...."THEY" refers to vacations.
At the same time I am not sure how to grammatically define what is "IT".
If someone can explain that it would be great.
My opinion is "E"
I agree with E. As par Erin note...
a. they originally seemed to
b. they originally seemed to
c. they seemingly? would cost originally?
d. it seemed originally that they would
e. it originally seemed (that) they would (cost).
This is a good start. For instance, B would need to be in past tense, seemed. In fact, I often teach GMAT and TOEFL students that the words original (and its derivations) and first usually require past tense.
Furthermore, the "past future" of would in E is more precise than the simple past in A (or that B is lacking, in case you're going to ask if B would be correct if we changed seem to seemed). Since we're talking about something we'd learn after a certain point in the past, would is better.
For example:
This Acura is a lot better than I thought it would be.
is better than
This Acura is a lot better than I thought it was.
In the first example, we are saying that something turned out to be true. In the second example, we are saying that we were not aware of a fact that was true at that time.
And in the charter vacations question, there is no fact that the travelers were unaware of when they purchased the charter vacation--after the original purchase of the charter vacation (and probably toward the end of the vacation), the charter vacation turned out to be more costly than they had at first believed it would be.
I hear different things every time. 
