A is the answer !!!:) hope it’s right
        
             
        
        
        
The answer is B. "He asked himself where it had come from and how; the past provided no explanation, and the future could not justify it."
This option is not a dark humor because it does not show the opposite side of happiness. The other choices explain that although there is happiness, he considered it as a burden- making it a dark humor. 
 
        
                    
             
        
        
        
An adverb clause is a dependent clause which cannot exist on its own, it has to be a part of the main, independent clause. So, having that in mind, the only dependent clause among these examples is 'when you return from California'. Therefore, the correct answer is B.
        
             
        
        
        
Answer:
the best resource would be a dictionary, but you can also look it up on the internet those would be the best 2