This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
Pre-carve burnishing is useful for all except: 
Select and explain. 
A. Bring further excess mercury to surface, B. Increase surface hardness, C. Decrease number and size of voids, D. Marginal adaptation
B: Increase surface hardness
Answer: B: Increase surface hardness 
Explanation: Objectives of Precarve Burnishing

Improves the marginal integrity of restoration.
Shapes the restoration according to contours and curvatures of the tooth.
Helps in reducing the mercuric content of amalgam.

Nisha Garg, Amit Garg. Textbook of Operative Dentistry.  Edition 3. Page: 341