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
Which of the following bacteria contains mycolic acid in the cell wall 
Select and explain. 
A. Escherichia, B. Mycoplasma, C. Mycobacteria, D. Staphylococcus
C: Mycobacteria
Answer: C: Mycobacteria 
Explanation: Mycobacterium are slender rods that sometimes show branching, filamentous forms resembling fungal mycelium. In liquid cultures, they form a mould like a pellicle. they do not stain readily, but once stained, resist decolourisation with dilute mineral acids, due to the presence of mycolic acid in their cell wall. They are called acid-fast bacilli. Mycobacterium are slow-growing, aerobic, non-motile, non-capsulated and non-sporing. Ref: Textbook of microbiology; Ananthanarayan and paniker's; 10th edition; Pg;351