Well, the words negative, positive, and world are all common words that are used in our everyday lives. So, I would choose C. Materializes 
Hope I helped!
        
                    
             
        
        
        
A is wrong you wouldn't say "is" you would say are. 
B is wrong to because "was" is not the correct verb to use.
D is wrong because key, should be plural, keys
C is correct, because it has subject and verb agreement.
        
                    
             
        
        
        
Answer:
decided immediately 
Explanation:
"impulsive"  in this context would mean deciding without thinking about it first