This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
Which one of the following statements best characterizes lympho-granuloma venereum (LGV)? 
Select and explain. 
A. The causative agent is C. trachomatis, B. In the United States, it is more common among women, C. It is most common in temperate regions, D. Penicillin is effective in early treatment
A: The causative agent is C. trachomatis
Answer: A: The causative agent is C. trachomatis 
Explanation: LGV is a sexually transmitted disease caused by C. trachomatis of immunotypes L1, L2, and L3. It is more commonly found in tropical climates. In the United States, the sex ratio is reported to be 3.4 males to 1 female. Tetracycline has been successful in treating this disease in the early stages; however, late stages usually require surgery.