Answer:
Hey. I just wanted to tell you what has been going on. I haven't been feeling like myself.  I've been busy doing school projects and other things. I started my own company. It has blown up real big. I barely have time to go to school and run my company but I'll get through it. Well, I just wanted to say that I wish you good luck with what you're doing.
Love,
Your friend (Insert name)
 
        
             
        
        
        
The correct answer is that they 'are not valid'. If the experiment is biased, it entails that it is not objective. For a experiment, and its results, to be valid, it had to be carried out objectively and taking into account all factors. 
It is possible that the results disprove a hypothesis, but to be certain it is necessary to see which was the original objective of the study, as it might also prove to some extent a hypothesis, which is probably also biased.
 
        
                    
             
        
        
        
I’m gonna have to say A. Details