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: Microbiology
A baker cut his finger while slicing a cake. After a week, site of the injury is red and swollen, and begins draining pus. While preparing some custard pies, he contaminates the dish with drainage from the lesion. The pies were eaten a day later by customers of the restaurant. Within 4 hours they developed vomiting with no fever. Most likely cause? 
Select and explain. 
A. Bacillus cereus, B. Clostridium perfringens, C. Escherichia coli, D. Staphylococcus aureus
D: Staphylococcus aureus
Answer: D: Staphylococcus aureus 
Explanation: This is the history of staphylococcal food poisoning. It is associated with consumption of milk and milk products containing preformed, heat-stable enterotoxin. The incubation period is less than six hours and main manifestation is vomiting.