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: Skin
A 30 year old male patient has a large, spreading and exuberant ulcer with bright red granulation tissue over the glands penis. There was no lymphadenopathy. The most likely causative organism is; 
Select and explain. 
A. Treponema pallidum, B. Herpes simplex virus type 1, C. Herpes simplex virus type 2, D. Calymmatobacterium granulomatis
D: Calymmatobacterium granulomatis
Answer: D: Calymmatobacterium granulomatis 
Explanation: D i.e. Calymmatobacterium granulomatis