Complementary colours are colours that are combined to make a grayscale off colours
A complementary pair is when you combine colours that are opposite of each other like red and green, or yellow and purple etc.
When you put two of these colours together they cancel each other out which leads to that grayscale of colours like grey or even brown
        
             
        
        
        
Well both etching and drawing show a whole picture, use ink, and both are considered sketches. 
These are just some simple similarities. Hope this helps.
        
             
        
        
        
Answer:
Turquoise
Explanation:
Scarlet:  red
magenta: red
orange comes from red and yellow 
I hope this helps!