Citation signals whether the decision has received positive negative cautionary or neutral treatment in judgements
        
             
        
        
        
I would go with B but wait for some one else to answer just in case 
        
                    
             
        
        
        
problem/cause/solution
The passage first identifies the problem as the tires "piling up in empty lots." Then it is explained how those tires got there: the cause. The author says that since "it is expensive and dangerous to dispose of tires" people don't dispose of them and they just keep piling up. Then the passage ends with a solution. The author mentions how tires can be shredded and turned into rubberized asphalt for paving projects. 
 
        
             
        
        
        
The answer is the first choice. Both verb tenses are in the past tense and agree with each other. 
        
                    
             
        
        
        
I'm thinking C it fits the most.