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
A 5-year-old residential school child walks into your clinic with the habit of thumb sucking in association with bruxism. Chemical approach for reminder therapy is: 
Select and explain. 
A. Ferrous oxide, B. Femite, C. Nail polish, D. Nail polish with flavor
B: Femite
Answer: B: Femite 
Explanation: Femite solution is primarily used to prevent topical infection over the skin. The active constituent of the medication is known to be the most bitter substance available. Just a few parts of it per million will make the product so bitter that children and pets would not be able to swallow it. The femite is applied in the thumb/finger which used in thumb/finger sucking.