This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
All are true about Bacillus except: 
Select and explain. 
A. Mc Fadyean's reaction is used in presumptive diagnosis of anthrax infection, B. Medusa head appearance of colonies in gelatin stab culture, C. PLET is the selective medium, D. Ascoli's thermoprecipitation test is used for laboratory diagnosis
B: Medusa head appearance of colonies in gelatin stab culture
Answer: B: Medusa head appearance of colonies in gelatin stab culture 
Explanation: Ans. is 'b' i.e., Medusa head appearance of colonies in gelatin stab cultureMedusa head appearance is seen on agar microscopy, Bamboo stick appearance seen on gram staining.PLET - stands for Polymyxin, Lysozyme, EDTA and Thallous acetate