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: Pharmacology
Which of the following is responsible for antibiotic-associated colitis : 
Select and explain. 
A. Clostridium botulinum, B. Clostridium perfringens, C. Clostridium difficile, D. Actinomyces species
C: Clostridium difficile
Answer: C: Clostridium difficile 
Explanation: None