Final answer:
The word that best fills in the blank is 'Speculation'.
Step-by-step explanation:
The word that best fills in the blank is Speculation. Speculation means the act of forming opinions or conjectures about something without firm evidence. In the given sentence, 'was rampant about whether the company was closing', it implies that there were widespread rumors or guesses about whether the company was closing. 'Speculation' fits this context perfectly.
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