This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal tract, Subject name: Pharmacology
Which of the stool softners doesnot interfere with fat absorption? 
Select and explain. 
A. Docussates, B. Phenolphtalein, C. Liquud paraffin, D. Castor oil
A: Docussates
Answer: A: Docussates 
Explanation: Phenolphtalein and castor oil are stimulant purgatives whereas docussates and liquud paraffin are stool softners.liquid paraffin may cause deficiency of fat soluble vitamins. (ref KDT 7/e p673-674)