capnx wrote:I pick C. I think "has changed little from what it was" is redundant. If something has changed, of course it would've changed "from what it was", so the second part in unnecessary.

Yes, that would be redundant. But that is not the issue.

"has changed little" = "has changed little from what it was"

But:

"has changed little" does not necessarily mean "has changed little from what it was in the last century"

If something has changed, then of course it has changed from the state it was in immediately before the change. But it is not so clear that it has changed from the state it was in during some time prior to the state it was in immediately before the change. (For example, it could have returned to its original state!)

Therefore, Choice C changes the meaning.

So, do I think Choice D is correct?
No, it is definitely grammatically incorrect. So are the other choices.

There is no correct answer.

This is a badly designed question, at least with the available answer choices. Would not be on the GMAT.

Don't know what the source is but I wouln't be surprised if it was 1000SC. Practicing with such materials can do more harm than good.

The Founder of this site had this to say about that source: https://www.beatthegmat.com/1000-scs-t27.html

There is a difference between "in the last year" and "last year".

in the last year, goes with present perfect.
last year, goes with simple past.

IMO C