The invention of the elevator in the mid-nineteenth century was significant not only for the convenience it represented, also it ushered in a new era in architecture, allowing buildings to become increasingly tall.
This is from MGMAT SC question bank.
I nailed the right answer but I am still not happy. I think "it" is kind of ambiguous and does not clearly refer to elevator(which is the intention!). The correct answer choice also has "it" but I guess it is correct as it is the "best" option, right? Thanks!