Everything you need to make a good  meaningful sentence (and grammatically correct, of course), is to follow common rules. Do not forget to provide your sentence with complexity, but you don't have to make them too complicated, I mean you need to use key words, they will make your thought completed. And the second point is that you need to properly organize the sentence using correct word order.  ion:
 
        
                    
             
        
        
        
A I'm sure it's helps keep the button on slik is too soft wood would not help a smaller button wouldn't help so A is the correct answer
        
                    
             
        
        
        
You would want to mix he dark one first so that you can slowly put lighter color I'm so you know how much to put in