Answer: The correct answer is C. Vacuum.
Explanation: It was correct on my test : ) 
 
        
             
        
        
        
The answer should be Non banded grains
        
                    
             
        
        
        
Answer:
1. c
2. d
3. a
4.b
Explanation:
I numbered the first four boxes a, b, c, and d, and the slots where they go in 1, 2, 3, and 4 going down.