(A) for me. Time taken 01:09.
If one knows the Type 2 conditional, then one can easily mark (A) and move on given that one has understood the meaning completely.
But let's see how someone who doesn't know those "Conditionals" can still reach to the right answer choice.
You can drop (C) and (D) for using "was". The meaning of the sentence is to hypothesize a scenario, thus the usage of "was" is incorrect. "Was" makes it look like an event from the past. If you've got the meaning pinned in your head, your can identify that this tense usage is incorrect.
(B) the structure in this is horrendous.
If there ever were..., it is in..... This choice seems to be doing some Dr. Strange stuff, mixing two parallel universes and their timelines.
(D) can be thrown into the bin for its usage of "should". In GMAT world, there are generally two uses of "should"- 1. moral obligation/duty. 2. Probable/possible event. None fits here.
Thus, only
(A) remains and looks like the best of the lot. Let's wait for the OA.
Posted from my mobile device
_________________