The fourth one (The small one).
        
             
        
        
        
If the roots of the equation f(x)=0 are -4,-1, 2 and 5, then binomials (x+4), (x+1), (x-2) and (x-5) are factors of needed polynomial.
Thus, the polynomial will have form
 where a is real coefficient (positive or negative). This polynomial has degree 4 as needed.
 where a is real coefficient (positive or negative). This polynomial has degree 4 as needed.
The form of the graph depends on the sign of coefficient a. Attached diagrams show two different cases of possible forms of graphs (first one for positive coefficient a, second one for negative coefficient a).
 
        
             
        
        
        

The distance traveled by the particle is given by the definite integral

where 

 is the path of the particle. The distance is then
