Answer :
It is A because speculation basically means rumours, so it is saying there were a lot of rumours about the company closing.
The correct answer is A. speculation.
The word speculation means the same as rumor - and the meaning of this sentence is that there were a lot of rumors about the closing of the company.
B. morose means sullen and gloomy; C. proclamation is an official announcement about something; D. affluency is the state of being rich. As you can see, none of the other options fit the gap above.