<span>practice effects and also collaborating </span>
        
             
        
        
        
Answer: A
Explanation:
A complementary good is a product that is used together with another product. Without its complement, such a good will have little value. When there is increase in the price of a particular product, the demand of its complement reduces because consumers may not be able to use the complement on its own. 
Complements have negative cross elasticity of demand i.e there is increase in the demand for a product when the price of its complement reduces. If bicycles and gasoline are complements, an increase in tax on gasoline will have a negative effect on the demand for bicycle. Due to the price increase of gasoline, less people will demand for bicycle. The initial change that will occur as a result of this is that as there is a price increase for gasoline, there will be a leftward shift in the demand for bicycle. This implies that less bicycle will be demanded for.
 
        
             
        
        
        
D. You should check to see if they align with yours and as a basis for a possible question
 
        
             
        
        
        
Answer: collaborative filtering
Explanation:
Collaborative filtering is a technique thta helps to filter out the things that a user can like base on how other identical users react. Here, a small sample of the people with similar taste will be chosen from a larger group.
When you view a selection at Amazon and see "Customers who bought this (item) also bought ...," you are seeing the application of collaborative filtering.