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
True about Clostridium tertium -a) Gram variableb) Terminal sporec) Produces exotoxind) Causes septic orthritis 
Select and explain. 
A. acd, B. bcd, C. abc, D. abd
D: abd
Answer: D: abd 
Explanation: Cl. tertium:

Nonexotoxin-producing, Aerotolerant, Gram variable
Oval and terminal spore – tennis racket shaped
Resembles lactobacilli
It is a rare human pathogen
Causes: Necrotizing Fasciitis and Gangrene, septicemia, septic arthritis

Apurba Sastry’s Essentials of Medical Microbiology 1/e p264