This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bladder Cancer, Subject name: Surgery
Risk factor for bladder carcinoma is - 
Select and explain. 
A. Clonorcis sinensis, B. Schistosoma hematobium, C. Plasmodium, D. None
B: Schistosoma hematobium
Answer: B: Schistosoma hematobium 
Explanation: Ans. is 'b' i.e., Schistosoma hematobium Risk factors for ca of BladderCigarette smoking is the main etiological factor and accounts for about 50% of bladder cancers.Occupational exposures to chemicalso The following compounds mav be carcinogenic # 2 naphthylamine-combustion gases and soot from coal# 4-aminobiphenyl-chlorinated aliphatic hydrocarbons# 4-nitrobiphenyl-certain aldehydes such as acrolein# 4-4-diaminobiphenyl (benzidine)-aniline dyes# 2-ami- 1-naphthol o Occupation reported to be associated with increased risk of bladder cancer# Autoworkers-metal workers# Painters-textile worker# Truck drivers-dye workers# Drill press operator-petrol workers# Leather workers-rodent exterminators & sevage workersSchistosoma haemotobium - Its a risk factor for both transitional cell ca & squamous cell ca.Drugs such as phenacetin & chlornaphazineCyclophosphamide therapyPelvic irradiationo Vitamin A supplements appear to be protective.