Hello,
To find the scale factor, we have to look at what's going on in the problem. 
In point A, we are converting from (5, 3) to (7.5, 4.5).
We can write and solve equation to find the change (scale factor)
5x = 7.5  and 3x = 4.5
If you solve either equation, you will find the scale factor is 1.5.
Good luck,
MrEQ
        
                    
             
        
        
        
None I would think because none of them are them because if you it is not the
        
             
        
        
        
Hmm
2 times 4=8
3 times 8 is not 27
1 times 1=1
2 times 4=8
3 times 9=27
aka
1 times 1^2=1
2 times 2^2=8
3 times 3^2=27
x times x^2=x^3
the rule is y=x^3