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
The culture medium used for corynebacterium diphtheriae 
Select and explain. 
A. Loeffler's serum slope, B. Tetrathionate broth, C. Selenite 'F' broth, D. Chocolate agar
A: Loeffler's serum slope
Answer: A: Loeffler's serum slope 
Explanation: • The usual media employed for cultivation of diphtheria bacillus are
1) Loeffler’s serum slope
■ It is used for rapid diagnosis as growth is shown within 4-8 hours.
2) Tellurite blood agar (Tinsdale medium)
■ It acts as selective media, as tellurite inhibits the growth of most other bacteria.
■ Growth may take two days to appear.