This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteriology, Subject name: Microbiology
True about Clostridium tetani is 
Select and explain. 
A. It is gram positive, B. Subterminal spores, C. Grows in aerobic environment, D. It is gram negative
A: It is gram positive
Answer: A: It is gram positive 
Explanation: Clostridium tetani is a gram-positive, slender bacillus, though there may be a considerable variation in length. The spores are spherical, terminal and bulging, giving the bacillus the characteristic "drumstick appearance". It is an obligatory anaerobe that grows only in the absence of oxygen. Reference: Textbook of Microbiology; Anathanarayan and paniker's; 10th edition; Page no: 264