If the decision _______ before he arrived, he would have been furious.A.was takenB.was being takenC.had been takenD.would have been taken

The correct answer to fill in the blank in the sentence is C. had been taken.

Explanation:

In the context of the sentence, we are looking for a past perfect form to indicate that the decision was made before another event (the person's arrival). The past perfect tense "had been taken" clearly establishes that the decision was completed before he arrived, which would evoke his furious reaction.

The other options do not fit the correct grammatical structure for conveying this meaning:

• A. was taken suggests a simple past action, which doesn't emphasize the sequence of events.
• B. was being taken implies an ongoing action that doesn't match the context of a completed action before his arrival.
• D. would have been taken is conditional and suggests a hypothetical situation that is not applicable here.

Thus, the answer is C. had been taken.