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
It is essential to lubricate dam before applying it. Which of these is NOT a suitable lubricant? 
Select and explain. 
A. Shaving cream, B. Liquid soap, C. Scrub gel, D. Vaseline
D: Vaseline
Answer: D: Vaseline 
Explanation: None