题目

 Yesterday I was shopping for a few items(物品).With nothing to do at home, my son, who just left university, was ready to go together with me. As I pushed the basket towards the register(收银机),I checked my items to see how many I had, thinking I might go to the Express Line(快速通道)where the sign said“Ten items or less”. I started to go to that line and my son said,“Mon, you have twelve items!”I said,“You know, but they’re close.” He said,“Why are you in such a hurry to get home? You should go to the Regular Line because you have over ten items.” Knowing he was 铁制自来水管与下列材料制成的水龙头连接，自来水管锈蚀最快的是（ ）A．陶瓷水龙头B．塑料水龙头C．铜水龙头D．铁水龙头