b. Because every other office is filled, we should convert Dr. Blake’s office into a lounge.
Explanation:
Looking at the sentence of the whole passage, the flow of the sentences is smooth until the parallel structuring of the sentences in the end. Instead of mentioning "<em><u>each and every one of the other offices</u></em>", the sentence can be made more fluent and easy flowing by just saying "<em><u>every other office</u></em>". This will also stop the monotonous flow of words. Also, changing the way of narration in the word "recommend" to a direct form of addressing the idea will make the statement more forward and direct.
Thus, the best revision for the sentence will be-
<u>Because every other office is filled, we should convert Dr. Blake’s office into a lounge.</u>
