GMAT Sentence Correction (SC) | Re: Announcing that one of its key successes had been the recent

I chose A because it uses the past perfect (had) instead of the present perfect (has). This isn't a continuing action. However, it is an action from the past that occurred before another past action (the start-up's claim).

I eliminated D/E because of the plural "their."

I eliminated C because of the use of present tense.

I didn't like the adverb "recently" in B and thought it was incorrect.

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