This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Skin
School of fish appearance is seen in? 
Select and explain. 
A. Bacterial vaginosis, B. Hemophilus Ducreyi, C. Gonococcus, D. Chlamydia
B: Hemophilus Ducreyi
Answer: B: Hemophilus Ducreyi 
Explanation: Ans. (b) Hemophilus DucreyiRef: Harrison 19th ed. /1012* School of fish appearance stained smear from genital lesions in cases of chancroid. Causative agent of chancroid is Hemophilus ducreyi.* H. Ducreyi a major cause of genital ulceration in developing countries characterized by painful sores on the genitalia. Another early symptom is dark or light- green shears in excrement.* Chancroid starts as an erythematous papular lesion that breaks down into a painful bleeding ulcer with a necrotic base and ragged edge.* H. ducreyi can be cultured on chocolate agar