问题
单项选择题
Which of the following is an early sign of laryngeal cancer()
A. Difficulty swallowing.
B. Chronic foul breath.
C. Persistent mild hoarseness.
D. Nagging unproductive cough.
答案
参考答案：C
解析：
Hoarseness occurs early in the course of most laryngeal cancers because the tumor prevents accurate approximation of the vocal cords during phonation.
