Total cloud inversion, which looks like a sea of clouds, occurs about

I also picked a , however want to understand Even if until recently is there why had been is used, it shall be has been

Had been need to be used when some past reference is there

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Hey Ankit,
Has Been is used for COMPLETED ACTION BUT CONTINUED EFFECT/ CONTINUED ACTION.In the sentence the action of not capturing ended recently by capturing it so effect is lost
Had been - Always remember when this is used, one should see either a time marker or a simple past.

Hope this helps

Can we eliminate C,D, and E on the basis of Subject Verb Agreement? Total Cloud inversion should use appears and not appear? Asking just to make sure if I am thinking in the right direction.

OFFICIAL EXPLANATION:

Creating a filter: In the original sentence, the verb "had been" raises a flag. As we saw in Punctuated Equilibrium, the past perfect must refer to a past point before another past point. That may be the intended meaning here: it had rarely been captured (=further past) until recently (=recent past). Tentatively keeping choice (A) in, we can go to the answer choices.

Finding objective defects: at a glance, the answer choices fall into two groups, the "occurs" and the "appear." We are talking about something grammatically singular, "inversion," so "occurs" is correct and "appear" is incorrect.

That leaves us with (A) and (B), which differ only in the placement of the phrase "at the Grand Canyon." One of these two options must be objectively incorrect. Which conveys the intended meaning? Choice (B) seems to say that total cloud inversion only occurs once a decade period -- as in anywhere. We don't have to be a meteorologist to know that's probably not right: it's at the Grand Canyon that it occurs once a decade.

The correct answer is (A).