This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
Which of the following is non cultiviable invivo 
Select and explain. 
A. Mycobacterium avium, B. HIV, C. Mycoplasma pneumoniae, D. Hepatitis-C virus
D: Hepatitis-C virus
Answer: D: Hepatitis-C virus 
Explanation: i.e. (Hepatitis C- Virus) : (432-35-Ananthanarayan 8th )Explanation : Some viruses are not culturable in vitro due to ack of susceptible cell lines, e.g. certain blood- borne (e.g. Hepatitis C virus, HCV) and water -borne (e.g. Norwalk virus) viruses.MYCOPLASMAMycoplasma - smallest free living organism known are prokaryotes that are bounded only by a plasma membrane* Their lack of a cell wall is associated with cellular pleomorphism and resistance to cell wall active antimicrobial agents such as penicilline and cephalosporins (beta lactams, vancomycin, Bacitracin)* The 'organism ' small genome limits biosynthesis and explains the difficulties encountered with in vitro cultivation (1068-H17th)* Myeo, pneumoniae can be grown on artificial media, but the process is exacting, requires special media and takes more than 2 weeks. Thus mycoplasma cultures do not provide any timely information* Mycoplasma are bounded by a triple layered unit membrane that contains s sterol therefore when mycoplasma are grown in culture media, the media required for the growth of the organsm should be rich in sterol (This is provided by adding 20% horse or human serum)