Carcass wrote:
We tried to ______________ a meeting between the two potential room-mates, but it was impossible to get them in the same room.
  
    | Two Answers | 
     
  
    | A. halt | 
    
  
  
    |  B. provoke | 
   
  
  
    |  C. engender | 
    
  
 D. induce | 
    
 E. fixate | 
    
    |  F. halt | 
    
  
Among the choices, A and F are the same, so this is not right.
Considering the choices from A through E.
The sentence is about "We" trying to do something about a meeting between potential room-mates which seems impossible.
A.  halt is incorrect, since no point in halting, which is already impossible,
B. provoke is incorrect, you can provoke a person, but not provoke a meeting, 
E. fixate is incorrect, since fixate is usually followed by "on", you fixate on something.
that leaves C and D.