It might be C but dont quote me on that
        
                    
             
        
        
        
He is using an arthroscope. Which is use to examine a joint. 
        
             
        
        
        
Answer:
Because Venus and Mercury are closer to the sun they are never visible at around midnight
Explanation:
I've read about this in articles
 
        
             
        
        
        
Answer:
Hmm, sorry, I do not think I have learned that yet.