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Answer:
E sharp and F natural sound the same. ... A double sharp is two half steps (one whole step) higher than the natural note; a double flat is two half steps (a whole step) lower.
Explanation:
give me bainly have a good day :P
 
        
                    
             
        
        
        
Answer - A. Engraving 
Simple Explanation Reason - Why it was difficult is because of learning the technique. Since it was less common then Printmaking used with etching. 
Credit Researched - Engraving - Wiki-Pedia