This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Chemotherapy, Subject name: Pharmacology
Tetracyclines are not useful for: 
Select and explain. 
A. Trichomonas, B. Chlamydia, C. Syphilis, D. Rickettsia
A: Trichomonas
Answer: A: Trichomonas 
Explanation: (a)chlamydial non specific urethritis(b)lymphogranulima venereum(c)atupical pneumonia(d)cholera(e)brucellosis(f)plague. (g)Relapsing fever*(h) Rickettsial infections: typhus, rocky mountain fever(i)syphilis ESSENTIALS OF MEDICAL PHARMACOLOGY page no.738