阅读下面短文，从短文后各题所给的四个选项（A、B、C和D）中，选出可以填入空白处的最佳选项。
In American culture, you may find some very sensitive topics that require you to think again before you put them forward. They are as follows:
Age. It is a very sensitive to many Americans. In this culture, the thought of growing older is a painful one and most of us, if , would like to have nothing to do with it. So many Americans work hard to a youthful appearance. The last thing they want to be asked is the unthinkable, “How old are you exactly?”
This question may result in a(an) like: “How old do you think I am?” Anyhow, if you are to know someone’s age, first you estimate（估计）their age by their . Then you take ten years away from that estimation. With a big , that person will probably say, “Thanks, but I am a few years older than that.”
Weight. This is one of the most sensitive subjects. In America, it is to be thin but it is a huge to be overweight. In any American fashion magazines, you’ll notice most are nothing more than skin and bones.
Income. You should never ever ask how much someone’s is. However, it’s perfectly to ask about their job title and what they do for a living. This information should give you some idea.
Matters of the Heart. This is a tricky （难处理的） one. Some people cannot wait to their hearts out to you. Then there are those who make sure their business stays behind closed doors. The general is not to get too personal. You don’t want others to think that you are their lives. , try not to ask too many questions until you have a(an) with this person.
Anyhow, it’s difficult to always an embarrassing conversation. So, be sensible, your mouth and try not to open a can of worms （虫子）.
