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
Nocardia is differentiated from Actinomyces by - 
Select and explain. 
A. Gram stain, B. ZN stain, C. Nocardia causes mycetoma, Actinomyces does not, D. Nocardia is faculative anerobe
B: ZN stain
Answer: B: ZN stain 
Explanation: Nocardia are partially acid fast while Actionomyces are non acid fast.