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
Which of the following is an obligate parasite- 
Select and explain. 
A. Mycoplasma, B. Chlamydia trachomatis, C. Gram -ve bacilli, D. Gram +ve cocci
B: Chlamydia trachomatis
Answer: B: Chlamydia trachomatis 
Explanation: None