Re: Since the results of his experiments matched those from laboratories w
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30 Apr 2021, 08:03
The first part of the sentence before comma is in contrast with the second part. If we try to isolate the word that indicates this is - flabbergasted. The scientist was not expecting something he discovered.
The first part conveys us that the scientist was feeling proud of the results because they stood up to most stringent quality standards somehow. This would have sounded like a good news to him.
But later, he must have found something bad that the supplier did. So, we need a word like - spoiled.
Only A fits best with my guess and the word adulterated definitely is suited to chemicals.
Therefore, A is my answer.