[单项选择]某化工厂男性管工，用气焊切割内壁附有大量水银的冷凝管2次，每次工作1小时左右。工作后，地面、头发、防护镜、两臂均见散布的水银，同时感到头昏、咽干、发热、无力、食欲减退、牙龈肿痛。查体：神志清，口腔黏膜充血，牙龈红肿、出血，颜面和两臂皮肤红色丘疹。体温38.4℃，尿蛋白（+），管型（+），诊断为急性汞中毒。若采用驱汞治疗，首选的药物是（）
A. 依地酸二钠钙
B. 硫代硫酸钠
C. 二巯基丙磺酸钠
D. 亚甲蓝
E. 任何金属解毒剂

The biggest problem facing Chile as it promotes itself as a tourist destination to be reckoned with, is that it is at the end of the earth. It is too far south to be a convenient stop on the way to anywhere else and is much farther than a relatively cheap half-day's flight away from the big tourist markets, unlike Mexico, for example. 　
Chile, therefore, is having to fight hard to attract tourists, to convince travelers that it is worth coming halfway round the world to visit. But it is succeeding, not only in existing markets like the USA and Western Europe but in new territories, in particular the Far East. Markets closer to home, however, are not being forgotten. More than 50% of visitors to Chile still come from its nearest neighbor, Argentina, where the cost of living is much higher. 　
Like all South American countries, Chile sees tourism as a valuable earner of foreign currency, although it has been far more serious than most in promoting its image abroa
A. Facilities in the ski resorts.
B. Domestic transport system.
C. Air services to Asia.
D. Road network in the south.