VitaminD佝偻病是位于X染色体的显性致病基因决定的一种遗传病，这种疾病的遗传特点之一是（   ）  

根据短文理解，从A、B、C、D四个选项中选择最佳答案。

    Almost everyone knows about Olympic Games. But not 1 people know how they started, why they once stopped and when the People's Republic of China took part in the Olympics.

    People 2 the first Olympic Games in Greece (希 腊）in 776 B. C. They had the Olympics 3 four years in summer. The first Olympics 4 for only one day and there was only one contest (比赛).It was a short race. Only Greek men could 5 in the race. Women couldn't 6 the race.

    When Rome (罗马）ruled Greece, the Olympics 7.

    The People's Republic of China took part in the Olympics 8 the first time in 1952. 9 China got no gold medals until (直到）1984 in the Los Angeles Olympics. China won the first 10 in the 29th Beijing Olympics in 2008. We hope China will get more gold medals in the 30th Olympics in London. Come on, the Chinese players!

洋务运动图自强，维新变法求立宪，辛亥革命建共和，在一次次的救亡图存中，中国汇入工业文明的大潮。这些活动（    ）

____ ÷____=____(套)

根据经纬网图，回答下列问题．