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
Inclusion bodies known as metachromatic granules helps the identification of which of the bacteriae? 
Select and explain. 
A. Corynebacterium, B. E.coli, C. Yersinia, D. Pseudomonas
A: Corynebacterium
Answer: A: Corynebacterium 
Explanation: Corynebacterium contain inclusion bodies, known as metachromatic granules, which are composed of inorganic polyphosphates (volutin) that serve as energy reserves and are not membrane bound. Internal metachromatic granules densely stain ruby red while the rest of the bacillus stains blue, when stained with an aniline dye such as toluidine blue O or methylene blue.