单选题 The most common symptom associated with bladder cancer is
A. burning on urination.
B. frequent infections.
C. painless hematuria.
D. decreasing urine output.

【正确答案】 C

【答案解析】Painless hematuria is the most common symptom associated with bladder cancer. Bleeding from the lesions occurs fairly early in the disease process, but bladder cancer is basically asymptomatic in early stages.