What’s the rest of the question this isn’t enough
The answer is not A, because it is not clear enough. Who's we?
The answer is not B, the sentence is not clear about the building they are visiting.
The answer is not C, it's not clear about what building they are talking about.
So your answer is D.
I think its Demonstrative
Answer:
Twenty-one people are to be divided into two teams, the Red Team and the Blue Team. There will be 10 people on Red Team and 11 people on Blue Team. In how many ways can this be done?