This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Urology, Subject name: Surgery
Most common route of infection in kidney tuberculosis 
Select and explain. 
A. Ascending infection, B. Lymphatic spread, C. Direct invasion, D. Hematogenous spread
D: Hematogenous spread
Answer: D: Hematogenous spread 
Explanation: Genitourinary tuberculosis (GUTB) accounts for 14% of non-pulmonary cases of TB. It is caused by dissemination of the organism through the bloodstream and is thus always secondary TB. ref : Bailey and Love 27th ed , chapter 76 , pg no 1405