This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacterial infection, Subject name: Medicine
Relative risk of developing TB in patients already infected with TB bacillus is highest in: 
Select and explain. 
A. Diabetes, B. Recent infection, C. Post transplantation, D. Malnutrition
C: Post transplantation
Answer: C: Post transplantation 
Explanation: Condition Relative risk of developing TB (in decreasing order) Post transplantation 20-70 HIV 30 Silicosis 30 Recent infection 12 Diabetes 3-4 Malnutrition 2-3