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: Radiology
Radiological appearance of 'thimble' bladder is seen in the following condition: 
Select and explain. 
A. Cystitis cystica, B. Chronic tuberculous cystitis, C. Neurogenic bladder, D. Acute tuberculous cystitis
B: Chronic tuberculous cystitis
Answer: B: Chronic tuberculous cystitis 
Explanation: Early tuberculosis of the bladder commences around the ureteric orifice or trigone, the earliest evidence being pallor of the mucosa due to submucosal oedema. Subsequently, tubercles may be seen and, in long standing cases, there is marked fibrosis and the capacity of the bladder is greatly reduced giving the radiological appearance of 'thimble bladder'. Ref: Bailey & Love's Sho Practice of Surgery 26E edited by Norman Williams, Christopher Bulstrode, P Ronan O'Connell, 2013, Page 1327-1328