A、B、C、D为初中化学常是的物质，它们之间存在如下图所示的转化关系．已知
B是密度最小的气体单质，D的水溶液呈蓝色．根据信息和图示回答问题（反应条件和部分生成物已略去）．
阅读下面材料，从每题所给的A、B、C、D四个选项中选出最佳选项。
The two girls and one boy are very popular in their countries(国家). Do you know them?
Name
Information
Harper Beckham
Fr om: England
Age: five
She can dance.
She can play the piano(钢琴).
She likes nice clothes(服装).
Suri Cruise
From: America
Age: ten
She likes nice clothes.
Wang Yuanye
(English name: William)
From: China
He can speak English.
He likes reading books.
①现代科学技术的不断发展 ②社会主义市场经济的发展
③人们文化生活品位的提升 ④人们的文化需求呈现多样化
